Yet Another Cycling Forum

General Category => Freewheeling => Velo Fixe => Topic started by: D.A.L.E. on 06 November, 2020, 05:15:54 pm

Title: Geared vs Fixed Bike Fit
Post by: D.A.L.E. on 06 November, 2020, 05:15:54 pm
All things being equal and with two identical frames. One being setup as a geared bike, one as fixed. Would you change anything in terms of fit? I.e. you'd drop the nose of the saddle on the fixed or have a little less width in the bars on the geared bike.
Title: Re: Geared vs Fixed Bike Fit
Post by: JonB on 06 November, 2020, 05:40:44 pm
I run them the same or as close as the frames and fittings allow. The only difference is I run 170mm cranks on my main fixed bike and 172.5 on the geared but I think this was to do with what I had available at the time to build up the fixed and since starting with that length I've stuck with it. There is an argument for running even shorter cranks on fixed to avoid pedal scrapes when cornering but I don't think I ever get over that far and it's not been an issue. I don't mess with saddle angles or heights, I have experimented with bull horns for fixed and quite liked it but currently running drops and not sure I'll go back to bullhorns (they were on a different bike that's moved on).
Title: Re: Geared vs Fixed Bike Fit
Post by: Ian H on 06 November, 2020, 06:09:47 pm
As near an identical set-up as possible for me. 
Title: Re: Geared vs Fixed Bike Fit
Post by: fd3 on 07 November, 2020, 03:15:44 pm
My geared bikes are laidbacks ...
Title: Re: Geared vs Fixed Bike Fit
Post by: sojournermike on 07 November, 2020, 03:36:06 pm
I’ve set them up the same, but 170 cranks instead of 175. That’s only because I couldn’t find a suitable chainset in 175 mind. The last time I scraped a pedal was over 30 years ago - racing the cars around York near the Barbican on my geared Orbit Gold Medal:)
Title: Re: Geared vs Fixed Bike Fit
Post by: LittleWheelsandBig on 07 November, 2020, 03:41:57 pm
My geared and fixed road bikes have very similar fits. The fixed has the handlebars slightly closer but that is mostly because it is mainly used as a commuter and I rarely ride on the tops in traffic.
Title: Re: Geared vs Fixed Bike Fit
Post by: drossall on 07 November, 2020, 04:09:09 pm
Mine are as similar as I can get them.
Title: Re: Geared vs Fixed Bike Fit
Post by: Deano on 07 November, 2020, 04:12:51 pm
Pretty much the same, just shorter cranks (165 mm on fixed, 170 mm when geared).
Title: Re: Geared vs Fixed Bike Fit
Post by: Tomsk on 13 November, 2020, 08:19:44 pm
Likewise: 165mm (72" gear as standard) on the main, long distance fixed, (170 x 68" on the winter fixed bike, just 'cos that's what was available) and 170 on gears. 44cm bars on fixed and roughstuff/tourer, 42cm on the geared audax bike. All now on Soma Highway One bars (https://www.somafab.com/archives/product/highway-1-bar), but a lovely short reach (75mm), square-ish shape but smooth curves (if you see what I mean), narrow radius bends and shallow drop with long rearward extension. First time I've got identical shape bars after decades of any old stuff on various machines, from Cinelli Campione del Mondo massively deep racing set-up, to narrow (38cm I think) '70s Randonneur bars.

165cm and a 72" gear is easier downhill - no knee pain in the latter stages of the last PBP, unlike two previous fixed editions. With my long legs, 165mm must be massively undersized!
Title: Re: Geared vs Fixed Bike Fit
Post by: Jakob on 14 November, 2020, 02:05:18 am
Drop saddle height 0.5".  It'll help you spin faster.
Title: Re: Geared vs Fixed Bike Fit
Post by: Hot Flatus on 14 November, 2020, 07:56:44 am
Same. If you are pedalling, you are pedalling.
Title: Re: Geared vs Fixed Bike Fit
Post by: Chris N on 17 December, 2020, 09:31:53 am
Shorter cranks and therefore a higher saddle.  I might put the bars slightly higher on fixed, but only so it's easier to get into the drops. 
Title: Re: Geared vs Fixed Bike Fit
Post by: rogerzilla on 18 December, 2020, 09:45:03 am
Shorter cranks and, ideally, a more rearward sitting position with an appropriately short stem*.  This makes things a bit safer when you grab a handful of front brake and forget to keep pedalling, which at some point you will.

*ok, my Harry Quinn track bike has a 130mm stem, but it has a VERY short top tube - probably a custom build for someone who wanted it to look as cool as possible
Title: Re: Geared vs Fixed Bike Fit
Post by: Jakob on 28 December, 2020, 03:39:50 am
Shorter cranks and therefore a higher saddle.  I might put the bars slightly higher on fixed, but only so it's easier to get into the drops.

Why shorter cranks? I run 175s
Title: Re: Geared vs Fixed Bike Fit
Post by: rogerzilla on 28 December, 2020, 10:29:03 am
Shorter cranks and therefore a higher saddle.  I might put the bars slightly higher on fixed, but only so it's easier to get into the drops.

Why shorter cranks? I run 175s
Cornering clearance and spinnability at 170rpm.
Title: Re: Geared vs Fixed Bike Fit
Post by: Chris N on 28 December, 2020, 07:09:59 pm
Yep.
Title: Re: Geared vs Fixed Bike Fit
Post by: sojournermike on 28 December, 2020, 07:28:13 pm
Plus, there aren't that many 175mm fixed/track cranksets.
Title: Re: Geared vs Fixed Bike Fit
Post by: Jakob on 29 December, 2020, 03:27:14 am
Plus, there aren't that many 175mm fixed/track cranksets.

Sugino, Shimano?
Granted, I got raised BB height, so corner clearance isn't an issue.
Title: Re: Geared vs Fixed Bike Fit
Post by: rogerzilla on 30 December, 2020, 11:41:38 am
Out of interest, how high? I find 10 3/4" is good enough with 165mm cranks but I'd want more than 11" with 175mm cranks. I tried my singlespeed as a fixie but it was scary - 170mm cranks and a 10.5" BB meant a couple of pedal grazes on mini-roundabouts before I put the freewheel back on!

(Apols for mixed units)
Title: Re: Geared vs Fixed Bike Fit
Post by: LittleWheelsandBig on 30 December, 2020, 11:51:46 am
With 170mm cranks, 11” is the absolute minimum BB height I am happy with on fixed, road or track.
Title: Re: Geared vs Fixed Bike Fit
Post by: Hot Flatus on 30 December, 2020, 11:58:38 am
I have never, not once in my life, experienced pedal strike, either fixed or geared.  172.5mm cranks on everything
Title: Re: Geared vs Fixed Bike Fit
Post by: LittleWheelsandBig on 30 December, 2020, 12:08:57 pm
I used to deliberately pedal strike during criteriums to disconcert wheelsuckers.
Title: Re: Geared vs Fixed Bike Fit
Post by: Brucey on 30 December, 2020, 04:32:27 pm
as important as BB height and crank length are both Q and the design of your pedals. Even the width of your shoe soles can be the limiting factor.

With most of my bikes (including my track iron) I would (in the dry) expect to get pedal strike before I ran out of grip. As LWaB implies, in certain kinds of racing you are flirting with pedal strike often. [I never got good enough to get a deliberate strike that didn't also threaten to tip me off...]

cheers
Title: Re: Geared vs Fixed Bike Fit
Post by: DuncanM on 30 December, 2020, 05:02:56 pm
I tore a Brooks saddle almost in half with my knee due to pedal strike on my fixie. Somehow I stayed upright - I don't know if the knee/saddle interface helped or hindered. The saddle was pretty old, but no amount of duck tape could make it rideable for more than a couple of miles. I now run 165mm cranks and M520s on the fixie (pedal strike was probably significantly contributed to by M454 pedals).
Title: Re: Geared vs Fixed Bike Fit
Post by: hubner on 30 December, 2020, 05:14:40 pm
Keep the bike more upright but lean the body more, or doesn't that work?
Title: Re: Geared vs Fixed Bike Fit
Post by: Chris N on 30 December, 2020, 05:28:31 pm
Dunno.  IME you just have to get on with it or slow down.  If you're insisting on riding fixed you might as well try to offset some of the risk by using shorter cranks and/or a higher BB.  I use 170mm cranks with a fairly wide Q on frames with a 290-ish mm BB height (60mm BB drop).
Title: Re: Geared vs Fixed Bike Fit
Post by: Ian H on 31 December, 2020, 01:08:43 pm
I've only had it a couple of times, resulting in a sideways hop of the back wheel.  The only danger on fixed is if you haven't enough road to straighten up on, though of course you will have scrubbed off a bit of speed. 
Title: Re: Geared vs Fixed Bike Fit
Post by: Brucey on 31 December, 2020, 02:14:59 pm
FWIW if your setup is a bit crap (low BB, long cranks, high Q and sticky-out pedals) then you won't be leant over very far when you get pedal strike and if the strike  is not too hard you may well be in a recoverable situation, with just a hop.  However if you have a setup which provides more cornering  clearance you are that much closer to the limit of grip when you get pedal strike and you are therefore more likely to come off, lowside.  The rear wheel hops, and then slides when it lands instead of regaining traction.

Reatively small changes in bike setup/geometry can make for in excess of ten degrees more (or less) cornering clearance.

With fixed gear setups, you can usefully gain a bit more clearance if you lean whilst pedalling, much as tricyclists must do when cornering. However it is neither comfortable nor terribly efficient to do this.

cheers
Title: Re: Geared vs Fixed Bike Fit
Post by: rogerzilla on 31 December, 2020, 02:23:03 pm
The usual practice is to take a wider line or slower speed around corners, but raised kerbs at chicanes, mini-roundabouts and adverse cambers can still be a problem.

Riding in a group with geared riders must annoy them: you are faster up the hills, slower down the hills and you can't take the same line around corners.
Title: Re: Geared vs Fixed Bike Fit
Post by: Jakob on 01 January, 2021, 07:08:49 am
Out of interest, how high? I find 10 3/4" is good enough with 165mm cranks but I'd want more than 11" with 175mm cranks. I tried my singlespeed as a fixie but it was scary - 170mm cranks and a 10.5" BB meant a couple of pedal grazes on mini-roundabouts before I put the freewheel back on!

(Apols for mixed units)

Erhh..standard track frame height, whatever that was. I still have the drawing somewhere from when I had the frame built..I'll see if I can find them.
High enough that I had no clearance issues at the local velodrome, with 47 degree of banking.
Title: Re: Geared vs Fixed Bike Fit
Post by: Doo on 16 January, 2021, 10:50:10 am
I always seem to be the odd one out... My fixie has a slightly lower saddle height compared to my road bike. I think this is mostly because my feet are at often times used as a brake... I'm still kinda new to this pixie thang...
Title: Re: Geared vs Fixed Bike Fit
Post by: citoyen on 16 January, 2021, 11:09:25 am
My geared and fixed road bikes have very similar fits. The fixed has the handlebars slightly closer but that is mostly because it is mainly used as a commuter and I rarely ride on the tops in traffic.

This is part of the reason I have crosstop levers on the fixed bike. I do think it probably needs a shorter stem as well though - I built it to the same fit as my fast road bike but I mostly use it for commuting so a more relaxed fit would make some sense.
Title: Re: Geared vs Fixed Bike Fit
Post by: Ian H on 16 January, 2021, 08:06:01 pm
I always seem to be the odd one out... My fixie has a slightly lower saddle height compared to my road bike. I think this is mostly because my feet are at often times used as a brake... I'm still kinda new to this pixie thang...

You can use the brakes, just like with gears.
Title: Re: Geared vs Fixed Bike Fit
Post by: Jakob on 17 January, 2021, 05:50:33 pm
I always seem to be the odd one out... My fixie has a slightly lower saddle height compared to my road bike. I think this is mostly because my feet are at often times used as a brake... I'm still kinda new to this pixie thang...

No, it's quite normal. It's easier to spin faster with a slightly lower saddle as well. It's just that this forum is odd :)
Title: Re: Geared vs Fixed Bike Fit
Post by: Goldcrank on 18 January, 2021, 12:49:12 pm
Slightly lower here too. I tend to use the fixed geared bike around town and for shorter rides where I will need to put my foot down. The road bike is for longer rides where I don't often have to stop. I also have a geared bike that I ride around town on and its saddle is at the same height as the fix.

Title: Re: Geared vs Fixed Bike Fit
Post by: Pedal Castro on 18 January, 2021, 03:23:06 pm
The shorter cranks on track bikes was to avoid right pedal strike when going slowly on the banking. Also a higher BB. I think my vintage track iron has 6.5" cranks.