Bike fit / correct riding position

good point. do you use a website/program to quickly work that out?

Good point. But not sure this looks 20mm different. (not ideal comparison photos, I know)

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Yep this one. Answer was 6mm (you’ll need to re-enter the details as whenever you go back to this site it defaults back to its own dimensions)

http://www.yojimg.net/bike/web_tools/stem.php

nice ! thanks

probably worth googling axle to crown of each

:)

Anybody know what the difference in stack heights between spd and spd-sl is for the same serious (7000/8000 etc)?

Struggling to match bike fit between bikes with different pedals despite the same shoes (lake cx237 vs mx237)

https://forum.bikeradar.com/discussion/12835970/stack-height-of-various-pedals

Cheers but I think that’s just road pedals?

You're right. I did have another link but didn't post. It's a few mm according to this.

https://forum.bikeradar.com/discussion/12891402/saddle-height-between-spd-and-spd-sl-pedals

I'm sure I've looked into this before, maybe even posted differences on here.

Speedplay:
https://www.lfgss.com/comments/14332578/

Time ATAC:
https://www.lfgss.com/comments/6781015/

SPDs:
https://www.lfgss.com/comments/8159952/

https://outerask.com/spd-vs-spd-sl-stack-height/
"Shimano’s XTR pedal stack up in terms of stack height? Well, it’s one of the lowest Profile pedals on the market with a mere 10mm of stack height. "

"Shimano Spd M520 Stack Height The Shimano SPD-M520 is a mountain bike pedal that was introduced in 1992. It features a stack height of 14mm"

"The M540 has a stack height of 12.7mm"

"The average stack height for SPD pedals is 14.5mm, while the average stack height for SPD-SL pedals is 9.5mm."

https://forums.thepaceline.net/showthread.php?p=3025620
One source reports that the XT XC pedals have a stack height of 18mm.
https://mtbgearbox.com/shimano-xt-vs-xtr-pedals/
That’s versus 13.7mm for Ultegra. XTR and DA are lower.
Then you’d need to consider the stack height of the shoe, e.g. the sole thickness.

Road pedal stack heights:
https://weightweenies.starbike.com/forum/viewtopic.php?t=164853

R8000: "Shimano has decreased the pedal’s stack height by 0.7mm"
https://www.cyclingweekly.com/reviews/pedals/shimano-ultegra-pedals

https://www.bikeforums.net/18470444-post1.html
"On the web I found a source that said 13.7mm for the Ultegra pedals (did not mention though if it's the 6800 or an earlier model) and 14.3mm for a Ritchey one-sided SPD road pedal which is the closest thing I could find to the PD-A600. Double sided Shimano SPD pedals are listed as 17mm. Then I guess the shoes play a role as well."

Cheers for all that hippy - did a bit of digging on the train in and found a lot of info on model specific stack heights of shimano pedals. Will pop it in here later in case it’s useful for anybody else

Nice one. I ride too many bikes now and swap between flats and Speedplay midfoot so my personal setup is all over the shop. It'd be different if I was riding 25hrs a week on the TT bike again.

Stack is measured from the BB so it also depends on the BB drop. The Giant has 2mm less drop so 2mm of the lower stack comes from there. Not a huge amount but it all adds up!

Hey ,

Where is a good reasonably priced place to get a bike fit in london ?

As promised, this may be useful for those of you who are equally affected by small changes in saddle height/obsessive/have overthought this way too much:

Pd-r9100 14.6mm (pd-r9000 14.6mm)
Pd-r8000 15.8mm (pd-6800 16.5mm)
Pd-r7000 16.5mm (pd-5800 assumed 17.2mm)
Pd-r550/rs500 16.5mm
Pd-m9100 15.1mm (9000 15.0mm)
Pd-m9120 15.4mm (9020 15.4mm)
Pd-m8100 16.5mm (8000 16.6mm)
Pd-m8120 16.1mm (8020 16.9mm)
Pd-m540 17mm
Pd-m520 17mm
Pd-es600 17.2mm
Pd-ed500 17.5mm

Another stack q. I’ve asked Surly the question but they’re yet to respond.

Would you assume their stack heights include the external lower headset cup of their recommended headset? Cane creek ec44/40 in this case.

EDIT: they’ve replied, and it does include it.

Some food for thought

https://www.youtube.com/watch?v=9n6nTNiacm8

Damn you helpful boi

they’ve replied, and it does include it.

this makes their geometries even worse than they are

My dura ace pedals (r9100) are 1mm less stack than the 6800/8000 and 105 I have. In terms of feel the only difference is clipping in and out, I don’t notice the very slight difference in stack height. Using the shimano blu cleats if that makes a difference….

It makes sense if you think about it.

Already bought one; your disdain for Surly only serves to confirm I’ve 100% made the right choice.

😂

I'm finding my saddle height now needs to be much lower than I'm sure it was a few years ago. It's around 74.5cm now. I know you can't do bike fit by looking purely at numbers (or on the internet), but for a 186cm tall rider of fairly average proportions (88cm inseam) seems to be a bit lower than the usual range. It has been in the high 70s in the past. It's not really an issue other than the 58cm frames I used to ride now seem too big. It doesn't feel too low and the leg extension and angle of knee seem fine. One difference now is I have the cleats slammed all the way back, but that can't account for it completely. Has any one had this before?

It does seem low. My starting point (or Greg Lemonds) would say 77.7cm. Is saddle fore/aft changed at all? You might feel the need to have it lower to bring bars nearer and compensate for over stretching? This is probably my best guess. Try it out on different (smaller?) bikes and see if you need the same.

Any injuries, body changes, changes to exercise etc?

My saddle has come down over time (cleats are all the way back too). The bike fitter I visited last year put it up by by about 5cm!! About a month later I got a hamstring injury which I fully attribute to that. ~4months off the bike and I'm now riding relatively pain-free, with the saddle at the previous lower position.