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-   -   Touring frame ground strikes (https://www.bikeforums.net/touring/1119915-touring-frame-ground-strikes.html)

rseeker 08-26-17 04:40 PM

Touring frame ground strikes
 
I've never owned a touring bike. Yesterday I test-rode a Fuji Touring. Not sure of the year, but a 2009 looks similar to what I rode. Anyway, it seemed really easy to lean over far enough for the pedal to touch the ground while getting on and off the bike.

Do touring bikes typically have low BB centers?

I'm only used to riding one bike, and that one's a mountain bike. I'm considering a touring frame as replacement, but my regular route has a lot of turns and I don't want to buy into a future of pedal strikes. ( I should have brought a yardstick to the store then I'd know. Next time. I just went into the store for tires...)

seeker333 08-26-17 04:49 PM


Originally Posted by rseeker (Post 19820069)
Do touring bikes typically have low BB centers?

Yes, for lower center of gravity and increased standover clearance, both which help on a loaded touring bike. I've never had pedal strike on my Surly LHT or DT with 175mm crankarms on paved roads. Fuji Touring has same BB drop as 700c Trucker.

Off-road bikes (mtb,cx,etc) typically have 10-20mm higher BB so crankarms are more likely to clear the irregular surface resulting from a lack of....road.

Only time I had occasional pedal strike was on a hardtail MTB converted to commuter duty, with a shorter rigid fork swap followed by smaller diameter tires, again with a 175mm crank. It usually takes a series of poor component choices along with aggressive turns/leaning to cause pedal strike. Even then it can be avoided by simply not pedaling through the apex of such a turn.

FBinNY 08-26-17 05:07 PM

Even with an extremely low bottom bracket, I wouldn't expect a pedal strike (on a paved road) under any normal conditions. It's possible that some bikes will make pedal strike possible if you pedal through high speed sharp corners, learning to coasting with the inside pedal up through these is SOP, and an easily acquired habit.

The pedals wouldn't tough when starting because the natural lean would be toward the side with the higher pedal.

If you are experiencing more than normal pedal strike (ie. with the bike leaning less than 30° from vertical) I wonder if there was a change from OEM spec. Things that increase the chances of pedal strike include wider pedals, longer cranks, and smaller wheels. In the category of smaller wheels, include materially narrower tires, is 25mm on a bike that was spec'd with 38mm.

jefnvk 08-26-17 05:26 PM


Originally Posted by FBinNY (Post 19820116)
Even with an extremely low bottom bracket, I wouldn't expect a pedal strike (on a paved road) under any normal conditions. It's possible that some bikes will make pedal strike possible if you pedal through high speed sharp corners, learning to coasting with the inside pedal up through these is SOP, and an easily acquired habit.

+1. I did it three or four times when I first went to road bikes, quite a shock, but you will learn your bike and how to power it in a hurry!

rseeker 08-26-17 06:01 PM


Originally Posted by seeker333 (Post 19820087)
Even then it can be avoided by simply not pedaling through the apex of such a turn.

Good point. Actually, I'm running pedal width extenders now for my 13 EEEE feet; I gave up pedaling through turns when those extenders went on. I don't even want to think about a pedal strike through the turn at the bottom of this one long downhill...




Originally Posted by FBinNY (Post 19820116)
If you are experiencing more than normal pedal strike (ie. with the bike leaning less than 30° from vertical) I wonder if there was a change from OEM spec. Things that increase the chances of pedal strike include wider pedals, longer cranks, and smaller wheels. In the category of smaller wheels, include materially narrower tires, is 25mm on a bike that was spec'd with 38mm.

I don't know what the original tire spec was, but the ones they had on there were quite skinny, maybe that's part of it.

FBinNY 08-26-17 06:26 PM


Originally Posted by rseeker (Post 19820192)





I don't know what the original tire spec was, but the ones they had on there were quite skinny, maybe that's part of it.

OK, so you'll be going with wider tires for touring, and that will raise the BB by the difference in width. ie. about 1/2" if going from 25 to 38mm.

BTW - low BB is highly desirable on a touring bike. You want to be able to put a toe down while still seated when you stop. Loaded bikes are unstable when held from the handlebars only, so staying seated as you plant a toe is a big plus.

djb 08-26-17 08:07 PM

I ride a bunch of bikes, and over all my years of riding, Ive had pedal strikes only a few times, and usually when Im in a rush and cranking through a city corner and leaning in more than usual because of being in a rush.
Really though, pedal strike is easy to avoid, and not an issue on a touring bike anymore than on other bikes.

DropBarFan 08-26-17 08:38 PM

Greg LeMond once mentioned that team-mate/adversary Bernard Hinault never pedaled thru sharp curves. Criterium bikes had a slightly higher BB to help pedal thru curves. 559mm/26" Surly Disc Trucker w/50mm-wide tires has no problem with pedal strike since I avoid aggressive cornering anyway since it can induce understeer & even front shimmy. At slow speeds I can pedal thru sharp corners.

Rowan 08-26-17 09:04 PM

One rule to remember: Inside pedal up.

The lower BB is desirable on a touring bike for reasons already stated.

Check the crank length. Likely on the Fuji, they are 175s. When the opportunity arose, I changed all my cranks to 170 because that is what I had on my fixed gear and it felt comfortable. Be aware, though, that shorter cranks require a slightly higher seat, and FBinNY's suggestion about remaining seated when stopped may or may not hold true.

Doug64 08-26-17 09:22 PM

Another reason for not pedaling through the corner while keeping the inside pedal up is to maintain good contact with the road. I was taught that when going into a fast corner to keep the outside pedal down and weight it going into the turn.

mstateglfr 08-26-17 10:17 PM


Originally Posted by rseeker (Post 19820069)
I've never owned a touring bike. Yesterday I test-rode a Fuji Touring. Not sure of the year, but a 2009 looks similar to what I rode. Anyway, it seemed really easy to lean over far enough for the pedal to touch the ground while getting on and off the bike.

Do touring bikes typically have low BB centers?

I'm only used to riding one bike, and that one's a mountain bike. I'm considering a touring frame as replacement, but my regular route has a lot of turns and I don't want to buy into a future of pedal strikes. ( I should have brought a yardstick to the store then I'd know. Next time. I just went into the store for tires...)

I doubt you would angle the bike while riding at the same degree that you had it while getting on and off the bike.

FBinNY 08-26-17 10:37 PM


Originally Posted by mstateglfr (Post 19820558)
I doubt you would angle the bike while riding at the same degree that you had it while getting on and off the bike.

That's funny.

I had the opposite reaction.

I KNOW how far you can lean a bike in a high speed turn, and how easy it is to have a pedal strike that way.

OTOH - I'm having trouble imagining how or why one would lean a bike that far at low speed when starting. Actually I can see the lean if one uses the so-called cowboy mount, but the lean would be away from the body, so the low side pedal would be high.

Can someone explain how the bike could be leaned that far with the low side pedal at 6 o'clock when starting?

Rowan 08-27-17 03:05 AM


Originally Posted by Doug64 (Post 19820487)
Another reason for not pedaling through the corner while keeping the inside pedal up is to maintain good contact with the road. I was taught that when going into a fast corner to keep the outside pedal down and weight it going into the turn.

Yep, there is a huge difference in how the bike feels, and especially if the rider has to make a sudden but subtle change in direction to avoid a drop-off edge on an apex, a pothole, or gravel.

It's also like poetry in motion riding behind someone coasting down a reasonable hill with sweeping corners watching the pedal positioning, the road positioning and the bike angle all working together smoothly.

One of my favourite memories on my old Fuji Touring was coming down The Sideling on a randonnee and coming fast into corners, braking really hard so the rear wheel was lifting off the ground slightly, and sweeping through the tighter corners with that inside-pedal-up regimen. Very exciting, and a wonderful feeling of bike and me working together.

BigAura 08-27-17 06:53 AM

If you're leaning your bike into a turn: you want the inside pedal up and you should be putting pressure on the outside pedal and kinda downward to keep at least the front tire gripping.

But to effectively turn a bike, lean is not required. I ride a fixed gear where pedal strikes can be a issue, for sure. Of course I have to manage my speed more into a curve and be aware not to lean much, but it can be done and really doesn't take that long to get used to.


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