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-   -   Pedals - why is there no spec (https://www.bikeforums.net/bicycle-mechanics/1040009-pedals-why-there-no-spec.html)

Ronsonic 11-29-15 06:28 PM

Pedals - why is there no spec
 
Why isn't there a published spec for pedal offset, q-factor, effective length, whatever you want to call the distance from the face of the pedal / crank to the centerline of the cleat grippers. There should be one. I'm recently not liking some pedals I own, feels like my feet are hanging off the end. And there's way too much space between the inside of my shoe and the crank arm.

These are some cheap pedals I'm looking to replace, and as I shop it would be nice to look at a number that tells me whether a prospective replacement will have this problem.

Andrew R Stewart 11-29-15 06:40 PM

I agree with the thought. I've tried some pedals and got rid of them because of too much arm to pedal clasp center too. Perhaps one more reason to shop in person where one can actually measure before buying. Andy.

gsa103 11-29-15 06:51 PM

Isn't that number relatively consistent among the different pedal systems? I can imagine it would be different between SPD, SPD-SL, Look, etc, but when you're making those changes, you're changing the cleat as well so some re-positioning is expected.

Jeff Wills 11-29-15 09:44 PM

On clipless shoes the cleat adjusts sideways so foot position depends on cleat adjustment. It's usually "best" to have your foot as close to the crank as possible without rubbing. For odd fitting situations (duck feet, Sasquatch feet, etc.) Speedplay offers different length spindles for their pedals: SPEEDPLAY ULTIMATE FIT VIDEOS or you can install Kneesavers: Kneesavers | Randy Ice | bicycle pedal extenders | mountain bikes | custom bike pedals | Pedal Adapters

Al1943 11-29-15 10:32 PM

I like Speedplay X-1 pedals because they have short titanium spindles with maximum ground clearance for short radius turns, minimum Q-offset, light rotational weight, maximum float, and can be released from any foot angle.

HillRider 11-30-15 07:57 AM

"Q" is also a function of crank arm design so any published measurement would have to specify the crank as well as the pedals.

Ronsonic 11-30-15 08:09 AM

What inspired this gripe was a pair of Exustar pedals that I'd bought years ago as backups that are "compatible" with Time Atac. The time came that I needed the backups and the Time system doesn't have a lateral adjustment.

So this is really all about my dissatisfaction with one product. But thought it was curious that nobody ever does publish a number for this. I like keeping my feet close together, I'm running the old, very narrow D/A 7410 cranks and usually have pedals and cleats so my feet just clear the arms.

HillRider 11-30-15 11:12 AM


Originally Posted by Ronsonic (Post 18353997)
What inspired this gripe was a pair of Exustar pedals that I'd bought years ago as backups that are "compatible" with Time Atac. The time came that I needed the backups and the Time system doesn't have a lateral adjustment.

So this is really all about my dissatisfaction with one product. But thought it was curious that nobody ever does publish a number for this. I like keeping my feet close together, I'm running the old, very narrow D/A 7410 cranks and usually have pedals and cleats so my feet just clear the arms.

I believe Time pedals provide lateral "float" as part of the pedal itself so they don't provide lateral adjustment in the cleat position. Another maker's "Time compatible" pedal can lack that float and still use Time's cleats so, while they are compatible they aren't identical.

As to Q-values, I've seen tables of Q-dimensions for a range of cranks so the info is out there.

Leebo 11-30-15 12:12 PM

Q factor is also determined by BB spindle length. Got a ruler to measure? Seems simple enough.

Andrew R Stewart 12-03-15 09:21 AM

Well I've had time to go through a number of different clipless pedals at work and home, taking crank arm face to center of cleat jaws dimensions. These measurements were done with a hand held vernier caliper and are likely within a mm or so or actual dimensions. I was impressed at how narrow the range turns out to be. Shimano SPDs of a few versions and vintages were all about 54mm. Crank bro. were about 53.5mm, as were the couple of Wellgos and Looks. Ritcheys were 52mm. On the road side I only had Looks of various versions and vintages which were all the same at 53mm. My Speedplay X2s are 53mm.

I haven't done this same exercise but with shoes. I suspect that the cleat mounting threaded points will have greater placement, WRT the actual foot, range. Also I suspect that for recessed SPD shoes (thing typical mountain shoes) the side to side adjustment ability, as limited by the shoe sole lugs, will have a range beyond that of the pedals. Lastly is the shoes "cant" or arch support. Both effect the foots placement and "feel" of how the legs work WRT the side to side motions during the pedal stroke. Andy.

HillRider 12-03-15 10:05 AM


Originally Posted by Andrew R Stewart (Post 18362869)
m. Also I suspect that for recessed SPD shoes (thing typical mountain shoes) the side to side adjustment ability, as limited by the shoe sole lugs, will have a range beyond that of the pedals.

The limitation on cleat side-to-side movement from interference with the sole's lugs can be altered easily with a Dremel and a sanding drum. Back when I rode Speedplay Frogs, the wide cleat wouldn't fit easily into some shoe models. The Dremel quickly solved that problem.

NukeouT 12-03-15 03:14 PM


Originally Posted by HillRider (Post 18353975)
"Q" is also a function of crank arm design so any published measurement would have to specify the crank as well as the pedals.

Yea, it seems that those kind of specs. would be like trying to hit a moving target, because they depend on an impossible to predict combination of other components. The industry probably does not focus on them as a whole either because the marketing would not sell more bike product. "Our pedals, now set 2mm closer!"

I did hear someone somewhere was working on a headset standard. Did they ever get that finished?

FastJake 12-03-15 03:37 PM


Originally Posted by NukeouT (Post 18363830)
I did hear someone somewhere was working on a headset standard. Did they ever get that finished?

Yep, except they didn't stop at one. They decided to make thirty of them :rolleyes:

Bezalel 12-03-15 04:00 PM


Originally Posted by FastJake (Post 18363896)
Yep, except they didn't stop at one. They decided to make thirty of them :rolleyes:

https://xkcd.com/927/

NukeouT 12-03-15 07:17 PM


Originally Posted by Bezalel (Post 18363951)

:roflmao:

Andrew R Stewart 12-03-15 08:10 PM


Originally Posted by HillRider (Post 18362988)
The limitation on cleat side-to-side movement from interference with the sole's lugs can be altered easily with a Dremel and a sanding drum. Back when I rode Speedplay Frogs, the wide cleat wouldn't fit easily into some shoe models. The Dremel quickly solved that problem.

While I agree and have carved or ground SPD soles many times (I worked in ski shops as the boot dimensions standards [DIN 78?] was just coming to market... we ground tips and heels on almost every boot we touched) this wasn't my point.

The point is that shoe cleat mounting hole positions are far less consistent from shoe brand and model to the next. So any pedal standards are only the part of the total. But the OP/s question was about pedals, not shoes. So I wrote to that and expanded to the rest of the system (another ski reference).

So with this let me tangent some... So Many People Expect that what they don't know isn't a factor. What isn't mentioned or specified isn't an issue. Pedals are easy to manufacturer to a repeated design, they only contact (to a large degree) other closely dimensioned components (crank arms and their cleats). But the shoes have to touch our bodies, which as we all know that there's no two alike. To me it's no wonder that shoes seem to be the bigger factor in "Q" range. Perhaps my speculation is unfounded but I doubt it.

I went through the pedal measuring exercise for a few reasons. To find out for myself, to be able to post here the findings, but also to confirm to a degree my suspensions about the likely contribution that shoes have in positioning feet/legs. This reminds me of the ski business back in the 1970s in that it was the footwear that was the harder standard to follow. Our industry would do well to follow the ski business's footsteps (intended pun) and start to establish some foot/cleat location standards. Or not, but at least publish some kind of placement guides or brand/model tendencies. Andy.


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