Folding Bikes - Softening the ride

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View Full Version : Softening the ride


cooker
06-27-09, 03:57 PM
I know this has been discussed, but I thought I would share this experience. When I got a Bike Friday NWT in 2007 I set it up for pavement with slick high pressure tires: 1.35" 100 psi. It's been great on new smooth pavement, but I was surprised at the harshness on any ruts, potholes, patches or other uneveness. It's not just the psi, of course, the smaller wheel radius also doesn't smooth out the bumps the way the 27" wheels on my old tour bike do at similar psi. I also found the folding bike unsteady and uncomfortable on even well packed trails.

I'm going to a departmental day party in a couple of weeks near Caledon Ontario, and some of the other non-golfers will probably head out on the well known rail trails in the area, so I researched how to adapt the bike for that. Somewhere on BF I saw that BMXers often put a fatter tire on the front to aid steering in loose dirt and someone had recommended that for folders too. If the front tire floats through a bad patch, the narrower rear one usually follows.

I looked into getting a second front wheel to swap when I plan to go off road, but I would want the same rim, (Sun CR-18) which is not hard core enough to be stock at a BMX store, and to get the local Bike Friday agent to build one would be too expensive, so I just bought a fatter 1.5" tire with a bit more tread and mounted it myself in 5 min. I figured I'd switch back to the other when I'm done that trip. I pumped it up to 70 psi, and dropped the original rear tire to 80 (I don't know how low I can go without risking a pinch flat) and just now went for a spin.

What a difference. I didn't have to cringe each time I saw any imperfection in the pavement ahead, and when I went on gravel it handled perfectly. I'm just going to leave the new tire on permanently for pavement or trails, and save the old one for when the rear one wears out.


Bacciagalupe
06-27-09, 06:07 PM
Yep.... A few other things you can add for extra comfort: bar-gels and a Brooks saddle.

I have a theory that adding weight (luggage) also helps out with road buzz, since the force of the small bumps is reduced by the additional gravity, and the shock waves spread out over more mass. I doubt it would help with a major pothole though.

DLW
06-27-09, 08:30 PM
We replaced Stelvios with 1.5" Marathon Racers with the same positive result. Some loss in speed, but significantly increased comfort on 2nd rate roads.

Seems like tire selection and pressures make more difference with 20" wheels.


AEO
06-27-09, 08:46 PM
Yep.... A few other things you can add for extra comfort: bar-gels and a Brooks saddle.

I have a theory that adding weight (luggage) also helps out with road buzz, since the force of the small bumps is reduced by the additional gravity, and the shock waves spread out over more mass. I doubt it would help with a major pothole though.

could just reduce the air pressure a bit, it does the same thing.
I'm not entirely sure how weight is distributed on a folding bike, but I just use the formula for full size.



Tire Width=20: Pressure(psi) = (0.33 * Rider Weight in lbs) + 63.33
Tire Width=23: Pressure(psi) = (0.33 * Rider Weight in lbs) + 53.33
Tire Width=25: Pressure(psi) = (0.33 * Rider Weight in lbs) + 43.33
Tire Width=28: Pressure(psi) = (0.33 * Rider Weight in lbs) + 33.33
Tire Width=32: Pressure(psi) = (0.17 * Rider Weight in lbs) + 41.67
Tire Width=37: Pressure(psi) = (0.17 * Rider Weight in lbs) + 26.67


Example: You are 150lbs running 28's

Pressure (psi) = (0.33*150) +33.33 = 82.83psi (rear)
Front Pressure = .9*Rear Pressure = .9*82.83psi = 74.55psi front