The bike that ate all the pies

a.twiddler

Senior Member
Since last summer I have been keeping an eye out for a drum brake 406 wheel for the Linear to give a wider choice of tyres for the front. The rim that came on the drum brake which was on it was a 440 size which takes a 500A tyre, a French size which just gives you a choice of Michelin 500A Confort white wall or .. that’s it. There’s a Dutch size which is a 438 which can be squeezed on if the tolerances are loose in the right direction. I managed to get one of those on quite easily but it’s a swine to get it seated properly if you have to take it off at all. At least it lets me use a Schwalbe tyre with a reflective strip and some puncture resistance, but although it runs well it’s not a long term solution.

A couple of weeks ago I bought a drum brake wheel from eb*y which stated that it was a “tandem front wheel from a Bike Friday”. The seller gave the spindle dimensions and they seemed compatible. My understanding of tandem drum brakes was that they were used on the back, as a drag brake in addition to rim brakes. The only difference I can see from a solo drum is that there is a “T” stamped on the torque arm, and the brake arm is a little shorter than the one already on the bike. The drum width and diameter are the same. The width OLN is 100mm while the original is 96, and the spindle diameter is the same.
Before:-
581101

After:-
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I had a couple of spare Schwalbe Big Apples in the garage, so for the sake of setting up the wheel I put one of those on. Plenty of clearance in the fork, the tyre is nominally 50mm but measures 44mm fitted. It looks enormous compared to the 37mm wide previous occupant. The diameter is noticeably smaller than the previous wheel with a lot of mudguard clearance, and the mudguard itself looks skinny. Hence “the bike that ate all the pies”. The mudguard looks as if it needs a good meal by comparison.

The Big Apple is wider than the rear, a Vittoria Randonneur 700 – 42C which is actually 38mm wide so my preconceptions lead me to expect that after a trial I will be looking for a 37 – 406 for the front. It’s not an off road downhill racer after all. With a lightly loaded front, a narrower tyre might concentrate the weight better for grip, though it will be interesting to see how the BA copes. It might be a surprise, in a positive way.

The Randonneur supposedly has high rolling resistance but as a rear tyre has supple sidewalls and a good thickness of rubber, but for the front something lighter would be desirable. Some puncture resistance and a reflective sidewall would be nice, to match the rear.

The brake has a decent amount of bite and feel on the stand but hasn’t been tried in earnest yet.

Also visible is my Mk1 home made frame fitted front rack, still on trial. I think it gives this great long bike a rather crocodilian appearance.
 
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a.twiddler

a.twiddler

Senior Member
Interestingly, Sheldon Brown gives support to the idea that the front wheel being wider than the back on a road bike is is not such a strange idea after all. He probably didn't have in mind a bike with such a long wheelbase that the front wheel is a distant speck on the horizon to the rider. I wondered if there were any long-time LWB aficionados out there with any experience or views on the subject. Still on the subject of food, the proof of the pudding is in the eating, will just have to suck it and see. I still haven't been able to escape for long enough yet to give it a meaningful trial.
 
Longtime Linear rider here. Actually, <pedant mode on> the Linear is a CLWB -Compact Long Wheel Base. There are a good many longer bents, especially in USA where they don’t have to bother with corners.

I have run marathons but mostly 2” Big Apples, but not mixed sizes fore and aft. The Apples I fitted for the ride on poorly surfaced tracks and they have been good. Handling feels marginally more sure footed upfront. Of course the weak point of long wheelbase designs is that the steering wheel is lightly loaded, so good grip is important.
I also like how fat tyres make it look a bit like a 1920s Mochet Velocar, aesthetics of course, being of fundamental importance on any bike that’s going to have to withstand a lot of being looked at.
 

404 Not Found Anywhere

Well-Known Member
I wonder if a wide tyre like a BA might actually help a lightly laden front wheel like on the Linear? A bigger contact patch, so better adhesion, should help in cornering and braking. You can run BAs at surprisingly low pressures without adding noticably to rolling resistance - I’ve run 30-40psi on my bent trike, on chip seal roads that works very effectively
 
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a.twiddler

a.twiddler

Senior Member
Interesting point about the length of the Linear. I assume mine is a medium as the main frame beam is 42" and according to the information sheet that came with it - "manual" would be stretching it a bit- frames were available in 36", 39",42",45" and 48" to suit inseam from 22" to34" and over, in steps. It seems like overkill as the Linear is so amazingly adjustable for most people as it is. I should supposedly be riding a 39" frame but mine has adjusted to fit me just fine.

How short does the bike have to be to be a CLWB? If the definition of LWB is just having the pedals behind the front wheel, and the original 80s USA LWB recumbents were mega long, where do we draw the line? Something like a Bike-E is obviously a CLWB, but how far can it be stretched before it becomes a LWB, and then something else again? If my Linear at 88" long, tyre tread to tyre tread, is a mere tiddler of a CLWB, in the land of the excessively large, the 36" frame is definitely one.
581344

Wandering OT now. Back to the front wheel. I managed to squeeze in a short ride of a few miles this afternoon and I must admit I had a few qualms before setting off. I had the pressure in the front tyre at about 35psi and was expecting some odd steering effects. I psyched myself up to launch and it was an anticlimax once I got rolling. The front wheel felt very ...planted, so much so that in comparison the tyre that it had replaced felt quite squirrelly. It was easy to ride in a straight line without thinking about steering input, and changing direction was easy. The BA rolls easily too. Now I've started to get used to it it doesn't look so enormous, though if it's going to stay the skinny mudguard is going to get replaced. It doesn't visually overpower the rear tyre as there is a good distance between them. It's a nice looking tyre, and looks good with the back one. As a bike that is a bit of an eyeball magnet, looks are more important than any other bike I've owned, not that I'd admit to being a poseur, of course! It certainly gives the front end a bit of a presence. It also seems to prove @404 Not Found Anywhere's theory about the larger contact patch, so far.
581345

Now I need to have a few proper rides on my familiar routes so I can compare how it performs compared to the skinny one.
 
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a.twiddler

a.twiddler

Senior Member
A few thoughts after a 23 mile test ride.

Although it doesn't seem like it ought to, the "tadpole bike" (wider tyre at the front than back) rides well and feels quite sure footed. On reflection, it is no more odd than having a 20" front wheel and a 700C rear. The steering is definitely more positive than with the previous 37c tyre (probably a fat tyre itself for many road riders used to 23C). There is some tyre noise from the front, certainly enough to be heard over the slight noise from the rear tyre, and more than there was from the previous narrower front tyre. Despite this, it runs easily, and certainly absorbs road irregularities. I have been running it at 35psi as that is the minimum recommended but the tyre feels well inflated at that pressure due to the light loading at the front. It might be feasible to run it at a few pounds less.

My feeling was that the average speed was slightly higher. Certainly my maximum speed was the fastest I've managed so far on the Linear though perhaps it was as much to do with more confidence in holding a line as downhill rolling ability.

It definitely feels that for the same effort, off road on my local railway trail the speedo reads faster, and I didn’t realise this until I took my attention from looking where I was going, to looking at the speedo. I have measured the wheel diameters since as I thought that the difference between a 440 and a 406 might be causing the 406 to turn faster and so register a faster speed but with the tyres fitted they are both 20” pretty much exactly across the tyre treads.

A few more miles are called for which might expose some drawbacks. So far, it seems all good.
 

404 Not Found Anywhere

Well-Known Member
I think people get a bit caught up with thinking about tyre width without thinking about what tyres do; smaller wheels will have a smaller contact patch than a bigger one if the width is the same, so to keep a similar amount of rubber on the road you need a wider section; plus there’s less air in a 20” tyre than an 700C one of the same section so for a similar amount of cushion you need a bigger section. Without reasonable suspension effect you are just going to be getting vibrated more and spending more energy combating this.
 

byegad

Legendary Member
Location
NE England
Re grip. My Kettwiesel trike has very little weight on the front wheel. About 12kg with me on it according to some bathroom scales I used when setting it up. As it weighs 17kg, plus what I've added with bags and tools, and I'm 100kg, that's 'not a lot'. Big Apples all round, 70psi in the rears and 55 in the front and it corners very surely.
 
I use a 50-406 Big Apple on the back of my ICE trike simply because it has more rubber to wear away before I get down to anything vital. This means I get around double the distance out of one vs a lighter tyre. I tend to use a lighter 40-406 tyre on the front wheels so they then wear at the same rate as the back and all three tyres end up getting changed at the same time. I keep all tyres around 60-70 psi.

Re grip. The back wheel of a tadpole trike is lightly loaded so it can be interesting trying to go up a wet/greasy/loose slope. If I do stall because the back wheel is just spinning with no traction then it can get even more interesting. My parking brake is on the back wheel and when I try to get off the load on the back wheel become less, Hence it can be a bit 50/50 if the back tyre has enough grip to even hold the trike in place on the slope as I get off.

Luck .......... ^_^
 
I ran that model & size tyre on the front of my Bakfiets for years. Fantastically sure-footed, faster than some of the skinnier tyres I'd used prior to it and never suffered a puncture. It gave the bike a really nice predictable feel in corners.
 
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a.twiddler

a.twiddler

Senior Member
Further update after a ride on 4/4/21. A day of contrasts, from being held back by the wind near the start to being given a huge speed boost on the way back, faster than I'm used to going. The bike felt fine. There were certainly no strange handling quirks revealed by this try out. I just equalled the max speed I reached one day last year, 32mph, and it feels stable enough at that speed that given the right situation I ought to be able to add a bit to it. It's very promising. It makes me wonder what the potential for speed from a Linear is, now having had a taste!
 
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