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-   -   Slow (https://www.bikeforums.net/folding-bikes/990401-slow.html)

tcs 01-22-15 07:38 AM


Originally Posted by fietsbob (Post 17488036)
Bike Friday's Tikit has more tire clearance..

Maybe, but mine has scary tiny clearance when fitted with Scorchers even sans fenders.

chagzuki 01-22-15 09:29 AM

Jur fitted a Scorcher on the rear of his Brompton, there's a thread about it. I don't think there's any point though, the suspension works great and a scorcher adds weight. On the front IMO it's an improvement. It does mean that the front wheel is closer to the floor when folded (I've got a rack and sometimes the front wheel touches the floor and rotates until the hub gear toggle chain catches on the spokes).

fietsbob 01-22-15 10:39 AM


Maybe, but mine has scary tiny clearance when fitted with Scorchers even sans fenders.
no personal experience like Yours . I just read Vic's Blog on that.

I put Schwalbe Marathon Plus tires on My Brommy ... Fast is not my goal , reliable Get on it and ride, transport, Is.
Marathon K was getting too easy to Puncture after 3+ Years Of riding.

Chag.. NB there is a Plastic guard cover for those indicator Chains from S-A ...

I scored Mine when I was Building up a 3 speed Trike, An un needed Part in that protected, middle of the frame jack shaft function..

1nterceptor 01-22-15 05:21 PM


Originally Posted by Schwinnsta (Post 17483771)
What makes the Brompton so slow?

In this video my Brompton is passing everybody:
https://www.youtube.com/watch?v=lmFU...6zPoymgKaIoDLA

In this one; a local club left me behind while I fiddled with my camera.
I caught up with them and my Brompton was the only one that didn't
walk when a steep hill came up:
https://www.youtube.com/watch?v=Jea4...6zPoymgKaIoDLA

1nterceptor 01-22-15 05:54 PM

Some mods that you may want to look into:

1. Schwalbe Kojaks at max PSI.
2. Lighter pedals
Both of these lighten rotating mass;
which is more beneficial than just lighter
parts(ti seat post, carbon saddle, etc.).

3. Aero/lowest position on the handle bars.
4. Stiffest suspension you can find/mod.
I'm using a green Birdy block.

https://farm4.staticflickr.com/3843/...a9b1187b76.jpgVan Cortland Park, da Bronx by 1nterceptor, on Flickr

dynaryder 01-22-15 06:29 PM

1 Attachment(s)

Originally Posted by Schwinnsta (Post 17490109)
Good to know? Will Scorcher fit on back? If not, why?

Apparently they will,but it requires futzing.

http://bikeforums.net/attachment.php...hmentid=429967

smallwheeler 01-22-15 07:11 PM


Originally Posted by dynaryder (Post 17491982)

serious doubts about the veracity of that article...

http://www.atob.org.uk/wp-content/up...ch-295x326.png

jur 01-22-15 07:23 PM

I had a Scorcher on mine's back as well. It was a very tight fit, I had to bend the mudguard stays to avoid the tyre rubbing. But it does clear the frame, unlike on older frames where it cannot fit.

The Primos are good tyres though, rolling resistance they are up there with the best of them. Not much good putting up with Scorchers if you already have Primos.

I fit a 58T chainring on mine and that had an immediate impact on speed. I was able to pedal on stretches where cadence made it uncomfortable with the 54T ring, and pedal harder on other stretches and reach higher average speeds. A 60T probably won't fit - the 58T ring already interferes somewhat with the front wheel hook when folding.

dynaryder 01-22-15 07:27 PM


Originally Posted by smallwheeler (Post 17492119)
serious doubts about the veracity of that article...

But the pic does show that Scorchers fit,which answers the question on the table.

jur 01-22-15 07:58 PM


Originally Posted by smallwheeler (Post 17492119)
serious doubts about the veracity of that article...

http://www.atob.org.uk/wp-content/up...ch-295x326.png

It seems they made that picture using equal tyre pressures for a widely-ranging tyre width, 40mm to 28mm. So the narrow tyre just about completely collapses, no wonder it looked weird. It might have been more real-world applicable to pump them proportionally the same, for same sidewall tension which is what determines tyre pressures. So a pity, at least for that picture they weren't comparing apples with apples.

Schwinnsta 01-22-15 09:43 PM


Originally Posted by jur (Post 17492221)
It seems they made that picture using equal tyre pressures for a widely-ranging tyre width, 40mm to 28mm. So the narrow tyre just about completely collapses, no wonder it looked weird. It might have been more real-world applicable to pump them proportionally the same, for same sidewall tension which is what determines tyre pressures. So a pity, at least for that picture they weren't comparing apples with apples.

The picture of the contact patch makes no sense to me. I would have assumed that the area of the patches shown should be the same. The weight of the rider of rider and bike being the same in the three tires and it is equal to the area of the patch times the air pressure. I'm confused.

jur 01-23-15 04:13 AM


Originally Posted by Schwinnsta (Post 17492489)
The picture of the contact patch makes no sense to me. I would have assumed that the area of the patches shown should be the same. The weight of the rider of rider and bike being the same in the three tires and it is equal to the area of the patch times the air pressure. I'm confused.

I suspect the narrow tyre suffered such a severe collapse that the sidewall deformed, also the contact patch, rendering the pure physics equation an approximation. The equation would be valid if the tyre is modelled as a pure elastic medium. Which for a soft narrow tyre it clearly is not.

bhkyte 01-23-15 03:18 PM


Originally Posted by jur (Post 17492824)
I suspect the narrow tyre suffered such a severe collapse that the sidewall deformed, also the contact patch, rendering the pure physics equation an approximation. The equation would be valid if the tyre is modelled as a pure elastic medium. Which for a soft narrow tyre it clearly is not.

iin the real world i find kojacks are faster as stevios are so firm i end up not peddling on roygh sections or some surface transitions.

fietsbob 01-23-15 04:49 PM


Originally Posted by dynaryder (Post 17491982)


Tight clearance is Between the chainstays and the front of the, tire sidewalls thats not shown...
[I know its just pasting a picture from the linked a to b page.]

(it really doesn't matter to Me , I put on Marathon Plus for the Puncture resistance, not speed )

MAK 01-24-15 12:22 AM

In Interceptor's second video regarding the bike club ride (post #29 ), at approximately 6' 10" of the video there is a white bike on the right side of the screen with a very strange (at least to me) drivetrain. Can someone tell me what it is? Thank you.

1nterceptor 01-24-15 03:48 PM


Originally Posted by MAK (Post 17495701)
In Interceptor's second video regarding the bike club ride (post #29 ), at approximately 6' 10" of the video there is a white bike on the right side of the screen with a very strange (at least to me) drivetrain. Can someone tell me what it is? Thank you.

Looks like a small gas motor. Didn't really hang out a lot with this club; so wasn't able to get a good look at everybody's ride.


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