rogerzilla
Legendary Member
I doubt the guys at Park see many Bromptons. That's how they are.
(Question) Can I easily swap the H handlebar with other types of handlebars to fit a shorter person?
- Thread starter Vg12th
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Kell
Veteran
- Location
- High Wycombe/London
That might be how they are, but no one else would set up a bike like that - unless it was at the owner's request.
Bit like how Brompton set up the bikes with the saddle as far forward on the rails as it will possibly go. I'm sure it suits some people, but it's not standard practice.
A lot will depend on how your arm meets the bar, obviously, and Bromptons are quite short, so the angle could be steep. But generally, in line with your forearm would be best.
Bit like how Brompton set up the bikes with the saddle as far forward on the rails as it will possibly go. I'm sure it suits some people, but it's not standard practice.
A lot will depend on how your arm meets the bar, obviously, and Bromptons are quite short, so the angle could be steep. But generally, in line with your forearm would be best.
berlinonaut
Veteran
- Location
- Berlin Germany
rogerzilla
Legendary Member
There is some wiggle room with Brompton handlebar controls but shifters/brake levers can hit the front wheel when folded, if you go too far. There is also a small effect on the way the cables hang.
Kell
Veteran
- Location
- High Wycombe/London
I don't want this to turn into a massive argument (especially as the whole discussion is off topic), but I'm not sure whose point you're trying to prove there. If it's that Bromptons are the same length as a 'normal' bike then normal rules apply to positioning the levers. Therefore my first post is correct that they're too vertical.
I, on the other hand, was trying to say that, actually, because the reach is shorter on a Brompton, then the brake levers could be at a steeper angle because your arms would meet the bars at a steeper angle. So actually conceding my earlier point. A lot of that will depend on the drop too.
That aside, road cyclists spend 80%+ of their rides on the hoods - which are clearly a good 3-4 inches in front of the grips on the Brompton in the image you posted. It's also irrelevant as it's a different bar and different brake set up.
However you look at it - and however long the bike is - having your levers mounted pointing directly down has got to be uncomfortable at best, and dangerous at worst. Maybe it's just angle angle of the photo.
It intrigued me, however. But as I couldn't find any reference online, I've just compared my bikes side-by-side and here's what I found.
26.5 inches - Brompton.
27.5 inches - 1999 Orange P7 MTB (I reference the year, because geometry has changed considerably in 20 years on MTBs)
32.0 inches - B'Twin Triban 3 (entry level el cheapo road bike)
33.0 inches - Giant TCR Advanced 1 mid level Carbon race bike.
In the interest of fairness, I took a measurement from the middle of each of my saddles to the left hand grip. However, look at any picture of a Brompton set up from the factory and you'll see the saddle is a good 2" further forward than mine, so I reckon you could take another couple of inches off the reach of the Brompton. In that instance, far from being 'the same' as a road bike - which is what I think you were trying to prove - my Giant would have a reach of about 8.5 inches more than the Brompton and even the way I have mine set up, it's 6.5 inches.
Also - this is on the longer frame Brompton - I'm not sure how much longer they are than the pre-2004 models.
ETA - I've googled this and the older Bromptons are 30mm shorter.
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Kell
Veteran
- Location
- High Wycombe/London
Saddle lined up in all shots.
Tops around two inches in front of Brompton bars, hoods about 5.5 inches in front. Also worthy of note is that the bar height of the Brompton is almost the same as the road bike - even though the road bike's front end is off the ground.
Again, I lined the seats up.
Hoods around 6.5 inches in front of Brompton grips.
Seats lined up.
Grips about an inch in front - and lower.
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12boy
Guru
- Location
- Casper WY USA
Actually my Brompton at 1045 mm has the longest wheelbase of my bikes, with 700c and 26 inch wheels.
Kell
Veteran
- Location
- High Wycombe/London
There are lots of crossed purposes I guess when comparing relative 'size' of bikes.
The wheelbase on my Giant (current model at least) is listed at 1020 - but the reach is way longer.
The wheelbase on my Giant (current model at least) is listed at 1020 - but the reach is way longer.
berlinonaut
Veteran
- Location
- Berlin Germany
I could turn your question back to you - in fact I should. Well - bike ergonomics is way more complex than you seem to assume, judging from your measurements and statements. Which leads you to wrong conclusions. The whole point was your statement "Bromptons are quite short" which is simply and obviously untrue as the wheelbase and my schematic picture show. Unlike many if not most other folders Bromptons do have a long wheelbase that is similar to many "normal" bikes or even longer. And the relevant contact points (saddle, bars, pedals) and their relations are as well. And surprisingly adjustable, especially the saddle as the Brompton pentaclip offers a way wider room for adjustment than usual plus the rails on the Brompton saddle do have a longer flat area than usual and do the same.
But now, that you have opened the can of worms based on your statement and came to very strange outcomes based on your assumptions unfortenately there's room and need for adjustment.
What you measured is one distance out of many, on your personal bike (which obviously hopefully fits you, but is obviously not a standard for everyone) and you compare it with one of your other bikes that again may be a reference or not. Plus your Brommi is modified: You use an H-stem with a non-factory bar - so this is not a factory setup but one you created yourself. We know that the H-stem offers less reach than the S-stem that would be a more typical setup for your bar height (and would offer more reach). Now you complain about your personal setup THAT YOU CREATED and fingerpoint to Brompton - how mad is that please?
Bike ergonmics and adjustment to the need of the individual rider or owner is individual and should be done by the shop who sells the bike. Obviously in most cases this is not done as most bike shops lack the competency and do not bother as do the owners. One outstanding from the crowd is Juliane Neuss, creator of the Brecki, the 8-speed-Nexus-conversion, the Bromptosaurus and the Bromptolino. She helped patria with creating their outstanding bikefitting machine, the "velochecker"
and uses it routinely to fit the bikes of her customers or to create individual bike designs for them:
https://junik-hpv.de/arbeitsbereiche/ergonomie-und-spezialanfertigung/
She's also written a book on bike ergonomics which sadly seems not to available in English (though it is in Spanish):
View: https://www.amazon.co.uk/Richtig-sitzen-locker-Ergonomie-Fahrrad/dp/366711107X/
so I would clearly call her a leading expert in bike ergonomics. As she is heavily into Brompton she routinely fits Bromptons to her customers with very good success - no issues whatsoever. There is an older pdf in Enslish available on her website that may give a rough idea, despite is dates from 2007: https://junik-hpv.de/wp-content/uploads/2021/02/Bike_Ergonomics_for_All_People.pdf
What she has to say about ergonomics on the Brompton and in general and about the relevant measurements, indicators, variables and goals for ergonomic bike fitting on different bikes and with different bars could not be more different from what you say.
I've done a bikefitting on her velochecker myself out of interest and compared the results with my (heavily individualized) touring Brompton that I had with me during my visit. Much to my surprise the outcomes were identical to what I had my bike adjusted to (over many years of tinkering and searching for the optimum). So blind-test passed I'd say. Plus I've now my setup checked by an expert and have a whole set of my personal parameters that I can easily match my other bikes to plus way more knowledge than before about what's important and how to act and tinker in case a bike lacks easy adjustability to a certain measurement.
So your claims are based on a totally oversimplyfied view of the topic, unsufficient measurements, that your falsely generalize plus they are even wrong. Not a perfect foundation for conclusions I'd say. Unsurprisingly your conclusions also seem to be way off - no wonder.
Regarding the brake levers: As @rogerzilla says their positioning on the Brompton is necessary due to the fold. There is some room for adjustability. While I would not setup them like they are on the Brompton if I had total freedom it is no issue in practice - it just needs a bit of getting used to. One of the things you have to live with on a folder or a Brompton. If you find this unacceptable there are plenty of other bikes available that you could switch to.
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Kell
Veteran
- Location
- High Wycombe/London
Actually, I think what you’ll find is that you’ve over-complicated the issue.
I may have used the wrong term when I said short. We’ve established that the wheel base on a Brompton is at least as long as a normal bike - maybe longer than some. I absolutely concede that point.
Let's start with where I should have started.
I made an initial claim about the positioning of the levers. They're sub-optimal in my opinion. If you have to rotate your wrist to access them - up or down - then when you need them in a hurry, they may not be available to you as quickly as you'd like. Yes you'd get used them, in the same way you get used to two levers to achieve 6 gears. But you also quickly forget. I've not been commuting for over a year, so when I took my Brompton out the other day I'd completely forgotten what each lever did. Especially as they're switched over from a normal bike where you'd expect to find the cassette shifter on the right and the chainrings on the left.
That's a diversion however.
I then said, actually you could get away with a steeper angle because your arms meet the bars at a steeper angle on a standard Brompton. Now, I didn't say the word standard, but that's what I meant and it's taken on a level of importance in your last post. If my assessment is null and void because I switched out one component, then your session with a bike fitter is equally null and void, because you say your bike was heavily modified. More so, because it's further from the norm.
Now I made a statement, which you wanted to disprove - and in part you did that, because you've proven that a Brompton's wheelbase is at least as long as road bike. Probably shorter than many modern MTBs, but that's an irrelevant measurement. That helps the stability of the bike and not the comfort or riding position of the rider. Not in and of itself anyway. Because everything else is dependent on the geometry of the bike and the rider.
The reason I oversimplified it, is because I was only interested in finding out one measurement. What's commonly referred to as saddle to bar reach, but I'd prefer the less technical term of arse-to-palm. The reason I don't like S2B reach is that it's measured from the front of the saddle, not where your arse goes. Some saddles are longer than others. But also, it's normally measured to the clamp - so doesn't take into account how forward your bars are. So in the diagram you posted above that measurement could well be similar on both bikes. But as road cyclists rarely use the tops (it's not 1984) it's useless for comparison.
So A2P as I shall refer to it now is an odd measurement because that's a result of everything else, which is crucial in this argument, but in itself is not of any importance in assessing the correct riding position for a rider.
Now, when I had a bike fit on my Giant - not on a jig (and not by someone who's written a book on the subject) - we started with my cleats, then saddle height and fore/aft position, flexibility etc etc. then worked out where my bars should be. So that's my default position.
I did have the MTB (and a Dahon Matrix), but I didn't have all the other bikes at that time. But that's the position I've tried to replicate.
And it's impossible. That A2P position of where my hands are on the bars on the Brompton compared to where they are on the Giant is impossible to replicate with standard Brompton components. For me. That's why I knew I wanted to fit bar ends and why I had to go for an H-type to allow the bike to fold with bar-ends fitted.
But you're right, an S type has a different curved stem which appears to put the clamp a whole 16mm in front of the one on a H type.
Now you've made a massive assumption that I know nothing about the subject of bike fitting. I'm not an expert, but I'm not a novice either. I'll admit, it's often a dangerous combination - as Neil deGrasse Tyson says, "One of the great challenges in life is knowing enough about a subject to think you're right, but not enough about a subject to know you're wrong."
But I've been following Neil Stanbury (arguably the go to guy for bike fitting expertise at the minute) and using his tips to see what I can do. In particular, I had my cleats set up the way most people do - mid way between big toe and little toe, but he recommends going further back. That has a knock on effect on seat height and position and then reach...
To that end, you spent years tinkering with your various bikes then had it checked to find out it was correct. Whereas I had one bike set up first to be correct and then me tinkering and getting mine to replicate the one I've already had assessed is somehow less valuable.
But here's what I do know. At 5' 11" I'm slightly above average height for a male in the UK. I know that me and a 5'11" bloke stood next to me could have vastly different set ups. My thigh bones are quite long for instance.
So it is possible, that if you're shorter than me that you could achieve the same position on your Brompton that you would on a road bike. You didn't mention a road bike as one of your other bikes, but I can only assume you've got one - as why else would you post a picture comparing a Brompton to a road bike.
I don’t want to put words in your mouth, but what you seem to be claiming is that out the box, your mate with her fancy jig could put every rider in the world in the same riding position as she would if she was measuring them for a road bike.
What I gleaned from the pdf you sent, however, is that the crucial measurement for her is the 90 degree angle between back and arm and that most city bikes are too short to achieve this - out the box. Presumably a consultation with her is not cheap, so most people just live with this.
But let's say we use that argument to assess the relative positions of the bikes you posted above:
If my road bike is correctly set up to achieve the 90 degree back/arm position on the road bike hoods. to achieve the upper body relationship on the Brompton the bars would have to be nearer and higher. Ergo, the bike is shorter in a horizontal plane, but the effective reach is the same. So one of those bikes isn't correct.
But transposing that image onto the picture you posted above to prove it: if the road bike was set up for someone using the 90 degree method, then in order for them to be 'correct' on the Brompton with a bar that is in a vertical plane above the grips means that their hands would be waaaaay above the 10cm difference your mate recommends.
I'd also like to see how she'd fit someone like Conor Dunne who, at 6'8" was the tallest rider in the Peloton and currently rides a 62cm Pinarello. The problem with Bromptons is that they are only one size frame. And because of the fold, there's very little adjustment to be made to the bars to increase reach. Over the years, I've seen some people in very strange riding positions on Bromptons. The most unusual was someone on a very old bike which looked to be a M type with flat bars. He was easily 6'4" and it appeared to all intents and purposes to be riding along almost vertically. It was as if he was sat on a wall and trying to lift a child onto it.
Now...
All that said, as I mentioned earlier, it's a pointless comparison for a number of reasons.
Road bikes and folding bikes are designed to do different things. Folding bikes are essentially compromised from the outset as they have another task to perform. Out and out aerodynamics aren't that important on a folder - certainly not for most people. So I'd imagine it's possible to set people up on a Brompton and make sure they're comfortable and don't suffer excessive back pain. But it will be much more upright than they would be on a road bike.
Secondly, the argument originally centred around brake levers and road bikes don't have brakes on the tops. Mountain bikes do. Hybrid bikes do, so that would have been a better comparison. As I mentioned in my not-very-scientific test there's not that much difference between the two when you compare those bikes side by side. Certainly with a shorter stem I could probably get my MTB to be very close to the Brompton.
I can't prove this, but I imagine more modern bikes might actually be shorter, because the riders I see today seem to be more upright. in the 90's XC was still a thing and MTBs were set up much more like road bikes - arse up, head down.
The reason for my test was not to be absolute proof. As you say, too few measurements, It was literally a case of 'really? I'm not sure I believe that, let's have a check'.
So what's the upshot of all this? I'd really have to be convinced you could set up a factory spec Brompton to replicate the ideal riding position on a road bike. It might work for shorter people. It certainly didn't work for me, but I'm not all people.
However, I will concede that a modern flat bar bike could be within a gnat's c*ck of being the same cockpit length as a Brompton. But many of those would be longer wheelbase and slacker gemetry.
All of which leads back to my original statement that the brakes shouldn't be set up like that. It looks like you could pull those with your thumbs.
For anyone wanting to be able to rotate them a little further into the optimal position, there are multiple versions of nipple extenders which give a few extra mm clearance to allow for a more correct positioning of the levers - even rotating M/H/P bars forward a bit if necessary.
Something like this:
I may have used the wrong term when I said short. We’ve established that the wheel base on a Brompton is at least as long as a normal bike - maybe longer than some. I absolutely concede that point.
Let's start with where I should have started.
I made an initial claim about the positioning of the levers. They're sub-optimal in my opinion. If you have to rotate your wrist to access them - up or down - then when you need them in a hurry, they may not be available to you as quickly as you'd like. Yes you'd get used them, in the same way you get used to two levers to achieve 6 gears. But you also quickly forget. I've not been commuting for over a year, so when I took my Brompton out the other day I'd completely forgotten what each lever did. Especially as they're switched over from a normal bike where you'd expect to find the cassette shifter on the right and the chainrings on the left.
That's a diversion however.
I then said, actually you could get away with a steeper angle because your arms meet the bars at a steeper angle on a standard Brompton. Now, I didn't say the word standard, but that's what I meant and it's taken on a level of importance in your last post. If my assessment is null and void because I switched out one component, then your session with a bike fitter is equally null and void, because you say your bike was heavily modified. More so, because it's further from the norm.
Now I made a statement, which you wanted to disprove - and in part you did that, because you've proven that a Brompton's wheelbase is at least as long as road bike. Probably shorter than many modern MTBs, but that's an irrelevant measurement. That helps the stability of the bike and not the comfort or riding position of the rider. Not in and of itself anyway. Because everything else is dependent on the geometry of the bike and the rider.
The reason I oversimplified it, is because I was only interested in finding out one measurement. What's commonly referred to as saddle to bar reach, but I'd prefer the less technical term of arse-to-palm. The reason I don't like S2B reach is that it's measured from the front of the saddle, not where your arse goes. Some saddles are longer than others. But also, it's normally measured to the clamp - so doesn't take into account how forward your bars are. So in the diagram you posted above that measurement could well be similar on both bikes. But as road cyclists rarely use the tops (it's not 1984) it's useless for comparison.
So A2P as I shall refer to it now is an odd measurement because that's a result of everything else, which is crucial in this argument, but in itself is not of any importance in assessing the correct riding position for a rider.
Now, when I had a bike fit on my Giant - not on a jig (and not by someone who's written a book on the subject) - we started with my cleats, then saddle height and fore/aft position, flexibility etc etc. then worked out where my bars should be. So that's my default position.
I did have the MTB (and a Dahon Matrix), but I didn't have all the other bikes at that time. But that's the position I've tried to replicate.
And it's impossible. That A2P position of where my hands are on the bars on the Brompton compared to where they are on the Giant is impossible to replicate with standard Brompton components. For me. That's why I knew I wanted to fit bar ends and why I had to go for an H-type to allow the bike to fold with bar-ends fitted.
But you're right, an S type has a different curved stem which appears to put the clamp a whole 16mm in front of the one on a H type.
Now you've made a massive assumption that I know nothing about the subject of bike fitting. I'm not an expert, but I'm not a novice either. I'll admit, it's often a dangerous combination - as Neil deGrasse Tyson says, "One of the great challenges in life is knowing enough about a subject to think you're right, but not enough about a subject to know you're wrong."
But I've been following Neil Stanbury (arguably the go to guy for bike fitting expertise at the minute) and using his tips to see what I can do. In particular, I had my cleats set up the way most people do - mid way between big toe and little toe, but he recommends going further back. That has a knock on effect on seat height and position and then reach...
To that end, you spent years tinkering with your various bikes then had it checked to find out it was correct. Whereas I had one bike set up first to be correct and then me tinkering and getting mine to replicate the one I've already had assessed is somehow less valuable.
But here's what I do know. At 5' 11" I'm slightly above average height for a male in the UK. I know that me and a 5'11" bloke stood next to me could have vastly different set ups. My thigh bones are quite long for instance.
So it is possible, that if you're shorter than me that you could achieve the same position on your Brompton that you would on a road bike. You didn't mention a road bike as one of your other bikes, but I can only assume you've got one - as why else would you post a picture comparing a Brompton to a road bike.
I don’t want to put words in your mouth, but what you seem to be claiming is that out the box, your mate with her fancy jig could put every rider in the world in the same riding position as she would if she was measuring them for a road bike.
What I gleaned from the pdf you sent, however, is that the crucial measurement for her is the 90 degree angle between back and arm and that most city bikes are too short to achieve this - out the box. Presumably a consultation with her is not cheap, so most people just live with this.
But let's say we use that argument to assess the relative positions of the bikes you posted above:
If my road bike is correctly set up to achieve the 90 degree back/arm position on the road bike hoods. to achieve the upper body relationship on the Brompton the bars would have to be nearer and higher. Ergo, the bike is shorter in a horizontal plane, but the effective reach is the same. So one of those bikes isn't correct.
But transposing that image onto the picture you posted above to prove it: if the road bike was set up for someone using the 90 degree method, then in order for them to be 'correct' on the Brompton with a bar that is in a vertical plane above the grips means that their hands would be waaaaay above the 10cm difference your mate recommends.
I'd also like to see how she'd fit someone like Conor Dunne who, at 6'8" was the tallest rider in the Peloton and currently rides a 62cm Pinarello. The problem with Bromptons is that they are only one size frame. And because of the fold, there's very little adjustment to be made to the bars to increase reach. Over the years, I've seen some people in very strange riding positions on Bromptons. The most unusual was someone on a very old bike which looked to be a M type with flat bars. He was easily 6'4" and it appeared to all intents and purposes to be riding along almost vertically. It was as if he was sat on a wall and trying to lift a child onto it.
Now...
All that said, as I mentioned earlier, it's a pointless comparison for a number of reasons.
Road bikes and folding bikes are designed to do different things. Folding bikes are essentially compromised from the outset as they have another task to perform. Out and out aerodynamics aren't that important on a folder - certainly not for most people. So I'd imagine it's possible to set people up on a Brompton and make sure they're comfortable and don't suffer excessive back pain. But it will be much more upright than they would be on a road bike.
Secondly, the argument originally centred around brake levers and road bikes don't have brakes on the tops. Mountain bikes do. Hybrid bikes do, so that would have been a better comparison. As I mentioned in my not-very-scientific test there's not that much difference between the two when you compare those bikes side by side. Certainly with a shorter stem I could probably get my MTB to be very close to the Brompton.
I can't prove this, but I imagine more modern bikes might actually be shorter, because the riders I see today seem to be more upright. in the 90's XC was still a thing and MTBs were set up much more like road bikes - arse up, head down.
The reason for my test was not to be absolute proof. As you say, too few measurements, It was literally a case of 'really? I'm not sure I believe that, let's have a check'.
So what's the upshot of all this? I'd really have to be convinced you could set up a factory spec Brompton to replicate the ideal riding position on a road bike. It might work for shorter people. It certainly didn't work for me, but I'm not all people.
However, I will concede that a modern flat bar bike could be within a gnat's c*ck of being the same cockpit length as a Brompton. But many of those would be longer wheelbase and slacker gemetry.
All of which leads back to my original statement that the brakes shouldn't be set up like that. It looks like you could pull those with your thumbs.
For anyone wanting to be able to rotate them a little further into the optimal position, there are multiple versions of nipple extenders which give a few extra mm clearance to allow for a more correct positioning of the levers - even rotating M/H/P bars forward a bit if necessary.
Something like this:
rogerzilla
Legendary Member
Certain Brompton types work best for people of certain heights. I'm fairly average (5' 10") and I like the S-type because I get a slight drop to the bars as on a normal bike, but my 6' 3" mate has pretty much the same drop on an M-type. Reach is compromised for him - it's about right for me - but excessively short reach is not usually a problem, especially for shorter trips.
I think shorter people face the biggest compromise as the bars will always be quite high and the reach rather long. M-bars can be tilted back a bit, but there are limits.
I think shorter people face the biggest compromise as the bars will always be quite high and the reach rather long. M-bars can be tilted back a bit, but there are limits.
Each to their own 👍... I'm 5'10" too and I find M bars and standard seat post at full extent is good for me. But I'm a pootling aging cyclist not a youthful lycra-clad sporty type (any more). Pass me the zimmer frame...
ExBrit
Über Member
- Location
- Southern California
You might be right, I am still trying to perfect the front end so maybe I'll move them.
12boy
Guru
- Location
- Casper WY USA
I had mine straight down and my DIL who wanted to try it out, took it up the steepish hill in our cul de sac, and then came down hollering that she couldn't find the brakes. She found them at last and wasn't injured but for some reason did not want to ride the Brompton after that.
