Brompton vs Road bike speed / efficiency

[mitchibob]

Yes it does. The aerobars are quick release (on and off in 30 seconds) but still very solid to ride. I did have some trouble fitting them onto the S-bar and had to make my own shims from the bands of hose clamps wrapped in electrical tape. I've dropped the bars another 4cm since I took this photo. The drops fold on either side of the front wheel. And those pedals are quick release SPDs from FlatBike. Add a Brooks B17 and you have a bicycle capable of some serious miles.

It still fits in an IKEA Dimpa bag.

View attachment 608522

It's well capable of serious miles without aero bars, and having used them on road bike recently, really like to have a really smooth, straight-ish road, and with Brommie, think I could only use them on a track. They definitely work, but can be terrifying... certainly don't blow my nose using them.

That said, could you clip them on and unclip them fast enough to do an hour record where bike had to be folded at the start and end of the hour, with the time saving of using them during the hour? I really think a brommie hour record, where bike should be folded start and finish, could but fun to see. Well, the start and the end ;-)

 

[Kell]

I'm surprised Brompton doesn't offer drops as a handlebar option.

I have to say - I'm not that surprised.

The Brompton may be a capable bike in other scenarios, but it is first and foremost a city/commuter bike.

Things like an Airnimal Chameleon would be a much more effective fast, folding bike - especially taking on board some of the learnings from that video about friction angles and rolling resistance.

 

[T4tomo]

But does it still fold nicely? (the biggest problem with the one I hired recently was a reach waaaay shorter than on my own bikes. Felt dreadful! And I much prefer drops to flats, AOTBE ...)

I only commuted on mine, but S- bars with (stubby -so allow the fold) bar ends, got you into a reasonable position, with not to far to reach for the brakes, without going to the excess of fitting drops. You also need time to get used to a Brommie if you've never ridden one.

 

[Kell]

But does it still fold nicely? (the biggest problem with the one I hired recently was a reach waaaay shorter than on my own bikes. Felt dreadful! And I much prefer drops to flats, AOTBE ...)

Don't say that to Berlinonaut, he won't have it.

I also felt the same with mine - so I fitted some old school bar ends from one of my MTBs.

What I would say as a word of caution though is that I deliberately went for an (old version of the ) H-type because the hinge is higher up the stem. On the original bike this meant the higher bars didn't catch the ground when folded. But I also gambled on it meaning that when I fitted lower, wider bars and bar ends, it would mean I could still fold it.

Which it did...

 

[rogerzilla]

If you want a faster bike with 16" wheels, try a Moulton F-frame. Not the easiest things to work on, and phenomenally heavy in their original state with chromed steel kit, but poor road surfaces don't upset them due to the full suspension.

 

[Kell]

I have to say, I thought they'd put too much emphasis on friction and rolling resistance, and not enough on aerodynamics. But I was watching it while doing something else, so they may be correct.

However, I take my basis from watching the Guy Martin 'Tandem' documentary where they tried to beat the record for the furthest travelled in 24 hours on a tandem. They didn't really bother trying to reduce rolling or mechanical resistance as they accounted for such a small proportion of what would actually slow you down. They interviewed Mike Burrows and his figures were:

90% air resistance.
7% rolling resistance
3% mechanical resistance.

From about 5:15 in the video below.


View: https://www.dailymotion.com/video/x3g0lqm

 

[Kell]

PS - I'm also very jealous of Guy's Orange Carb O

 

[rogerzilla]

The percentage due to air resistance is higher at higher speeds, though. For most Brompton riders, it's probably 50%.

 

[matticus]

The percentage due to air resistance is higher at higher speeds, though. For most Brompton riders, it's probably 50%.

Yup. the quote above doesn't mention that the 24h record will be well above 20mph. Average amateur/leisure Brommie ride? Quite a lot slower, I predict - and it's a v^2 realtionship ...

 

[rogerzilla]

I volunteered to help test some proposed new road markings/rumble strips today and took the Brompton as they wanted a wde variety of bike types. The Brompton was actually no problem due to its wideish Kojak tyres, although the vibrations did make the rear end clank once (no clip, hard suspension block). Apparently the road racing bike on 23mm tyres was more inclined to get upset.

 

[ExBrit]

I think it's great that people who make these decisions are asking cyclists for input. Thanks for representing us. Where I live, CalTrans just does whatever they feel like, so it seems. Don't you love the way this bike lane ends in a row of parked cars with no warning?