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    Bicycle just a hair too tall: Shorter cranks?

    Hello,

    I found an old Peugeot and I can clear the top tube standing over it, although it's a little close............closer than my other rides. I don't find that a problem for me, but I'd like to be able to bring the seat up a bit higher for some horizontal reach adjustment. However, doing that means I can't reach the pedals comfortably. So, I thought I'd do some web searching and it seems installing a shorter crankset might do the trick. I'm not seeing anyone reporting any problems running shorter cranks, but I thought some more person to person feedback from folks might help make a decision.

    Currently the bike has 170mm cranks.........Stronglight, btw. But, I have an SR crank that's 165mm. I know that would help some with the situation, but how much shorter can I go before things start to get whacked with gearing and high cadences? Would 160 or even 155 be going too short? And, any idea from personal knowledge/experience on how much more seat height this may net me...... given I use the same seat, of course?

    Thanks for any input! Ride it like you stole it!

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    Bump???

  3. #3
    Fred-ish rogerstg's Avatar
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    While reach may be affected by changing seat-post height, its not the primary method of adjusting it. Use the fore-aft saddle adjustment long with stem length and handlebar positioning and style. You should do some internet research about overall fitting because you are fundamentally off in your approach. Peter White had some pretty good basic info.

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    coprolite fietsbob's Avatar
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    if you cannot straddle the frame flat, bare, footed,
    with clearance of more than zero,
    get another one, that you can.

    or, always ride with rather thick soled platform shoes..

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    I don't understand how raising the seat would help horizontal reach. Set the saddle height and its fore and aft position so it is comfortable; then adjust thehandelbar height and reach.

    You don't say how old the Peugot is and whether it has French or English threads and stem diameters. Later Peugots had English.

    Stronglight spindles probably have a different taper than SR, so it might not be a good idea to change cranks. 5 mm isn't that big a difference.

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    It sounds like the bike is just too big for you. Going below 170mm probably isn't a great idea unless you have extremely short legs. What size is the frame?

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    That's just it........while my legs aren't extremely short, they are kinda short.........like 30in inseam and I'm 5'7. Yeah, I know the frame's a little too tall, but I like the bike and was trying to think of a way that I could remedy my situation without getting rid of it and have some fun with it. I don't know.....maybe even flip it in the future....whatever, though. Anyway, I've got other bikes that fit fine, so finding one to fit's not an issue. I just like this one...what can I say? It's nothing special. From all I can gather, it's a late 70's UO-8. Not sure on the exact frame dimensions, but suffice it to say the stem is at max height trying to keep it more level with the saddle and by eyeball comparison to other stems, it's 80mm length in reach. An Atax with drop bars, btw. The seat itself is already adjusted as far back as it will go. I don't know........maybe the BB's lower than on my other rides giving for a longer seat tube. I just haven't bothered to measure anything with a tape. I used a brake cable to gauge and compare to my Dawes frame and the HT and TT are about the same. But, the seat tube is about a centimeter longer by eyeball. So, I thought a different crank might do the trick. I know I can install an SR BB spindle to suit the SR crank that's 165mm........I did the same conversion for a friend that has a Peugeot. I just thought maybe a crank with 160mm might give me even a little more room to play given that raising the seat will push it further back from the handlebars.

    So, from what you all are saying installing a shorter crankset isn't a good idea.....well...why wouldn't it be? I know it'll feel different than my other rides, but what's the harm? Is there one? Have any of you ever done it? Just askin'. Hmmmm.....maybe I'll just go ahead and try it.

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    Boy howdy! Playin' around with keywords, I finally found this site:

    http://www.myra-simon.com/bike/cranks.html

    I have no idea what the exacts measurements are on my legs, but I guess I'm gonna find out. And, had no idea people got this "scientific" about riding a bike.....ha! When I was five, one day I just hopped on my big sister's bike and started riding. Guess I kinda skipped the course on calculations.

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    Crapola..........I think I just opened a can of worms for myself:

    http://www.nettally.com/palmk/crwives.html

    Thanks to my bright ideas........woohoo, got some reading to do.

    Thanks for your time, folks. I'll be back after my head's finished exploding.

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    Fred-ish rogerstg's Avatar
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    Quote Originally Posted by thook View Post
    I found an old Peugeot and I can clear the top tube standing over it, although it's a little close...
    Yeah, I know the frame's a little too tall,
    It doesn't sound too tall. The TT is not lined with razor blades after all.

    ... stems, it's 80mm length
    FWIW, That's VERY short for a road stem.

    I suggest that you compile fit information about your bike that fits well, and see if you can apply the specifics to the new bike. I've used the Park Road Position Chart for this.

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    Bianchi Goddess Bianchigirll's Avatar
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    I agree changing the seat height for reach is a bad idea. do you another bike that fits and is comfortable? if so measure it with the pedal at the 6 Oclock position to the top of the saddle. then set the Pug up with the same measurement. if that is comfortable to ride and pedal change the stem to adjust reach.
    Bianchis '87 Sport SX, '90 Proto, '90 Campione del Fausto Giamondi Specialisma Italiano Mundo, '91 Boarala 'cross, '93 Project 3, '86 Volpe, '97 Ti Megatube, , '90 something Vento 603,

    Others but still loved,; '80 RIGI, '80 Batavus Professional, '87 Cornelo, '09 Motobecane SS, '?? Jane Doe (still on the drawing board), '90ish Haro Escape

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    Quote Originally Posted by rogerstg View Post
    It doesn't sound too tall. The TT is not lined with razor blades after all.



    FWIW, That's VERY short for a road stem.

    I suggest that you compile fit information about your bike that fits well, and see if you can apply the specifics to the new bike. I've used the Park Road Position Chart for this.

    Haha....yeah, I guess it's not really, huh? Otherwise I'd be a unick by now. I mean, I can stand over the thing with shoes and the wheels on without actually resting on the TT. It's just my body dimensions and frame design givin' me the fitment issue. There again, the gentleman above did say judge standing clearance bare footed.

    So, 80mm's is considered very short? Interesting. All of my bikes (save a couple of more modern mountain bikes) are vintage type bicycles......between mid 80's and early 70's. And, all of them have come with this length of stem. Atleast, the ones I decided would actually work for me and ride. I guess that length was just common choice for bicycle retailers back in the day? I did run a quick search this morning on ebay for French stems at 100mm length. Seems, at the moment, I could spend anywhere between $30-$50 just to have one decent looking. Yeah......hmmm.........don't think I want to spend that for something that will only fit one thing.

    I've only read bits here and there of the links I posted so far. It's all I had time for once I found them. I guess I'll finish up some research before I jump on anything at all.........the link you've supplied included.

    Okay....thanks. Tah!
    Last edited by thook; 04-09-11 at 12:48 PM.

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    Senior Member tpelle's Avatar
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    Quote Originally Posted by thook View Post
    That's just it........while my legs aren't extremely short, they are kinda short.........like 30in inseam and I'm 5'7.
    I don't think that's particularly short!

    I'm 6'1 and I have a 36" standover clearance. When I got fitted for a bike the guy that did the fitting mentioned that I had long legs and arms relative to my torso.

    When you say "inseam", are you talking about your pants size, or are you talking about your standover clearance? As I said, I have a 36" standover clearance, but my pants all have a 32" inseam. Standover clearance is the important measurement on a bike, of course.
    Steel Club = BF-STL-00064

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    Quote Originally Posted by Bianchigirll View Post
    I agree changing the seat height for reach is a bad idea. do you another bike that fits and is comfortable? if so measure it with the pedal at the 6 Oclock position to the top of the saddle. then set the Pug up with the same measurement. if that is comfortable to ride and pedal change the stem to adjust reach.
    I'd already considered changing the stem, but that's another ordeal in itself. An older French stem for a chunk of change that only fits French bikes. Suppose it doesn't matter if I knew I was definitely, eventually selling the entire bike, but don't know about that, yet. Like I said, I'll do some more reading and come to some sensible conclusion before I do anything.

    BTW, this is something I guess I didn't mention already. So, the stem is at max height, the saddle's as far back as it'll go on the binder, but I don't have much seat post exposed at all with it's current adjustment. Could it be that the seat tube angle itself is more relaxed than say the Dawes that does fit? Heck......I dunno. I'm just pokin' it with a stick.

    Later

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    Meh.......I guess I'm gonna run down to the re'cyclery and see if they have a stem on the odd chance.
    We shall see...........

  16. #16
    Bianchi Goddess Bianchigirll's Avatar
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    I think we need to know more about this Pug. can you post a pic? are you sure it is french?
    Bianchis '87 Sport SX, '90 Proto, '90 Campione del Fausto Giamondi Specialisma Italiano Mundo, '91 Boarala 'cross, '93 Project 3, '86 Volpe, '97 Ti Megatube, , '90 something Vento 603,

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    Lol......am I sure it's French? I didn't know anyone else made early Peugeot bicycles and parts. But, the stem says Atax and is a hair smaller in steering post diameter than the SR stem on my Trek that's 22.2mm. So, I'd have to guess it's the size I've been reading of at 22.0mm. I don't have any calipers to measure exactly. Also, I don't have any pics of the thing. I honestly didn't think I was going to have to go to much trouble getting it where I wanted. I'm about ready to blow it off. It's not that big a deal to me. I just thought I'd give it a shot. In the process, I'm learning a few things, though. That's always nifty.

    If something happens in my favor, I'll post up the results. Thanks for all the input, folks.

    BTW, the re'cyclery didn't have anything remotely French...haha. Not surprised...

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    Quote Originally Posted by tpelle View Post
    I don't think that's particularly short!

    I'm 6'1 and I have a 36" standover clearance. When I got fitted for a bike the guy that did the fitting mentioned that I had long legs and arms relative to my torso.

    When you say "inseam", are you talking about your pants size, or are you talking about your standover clearance? As I said, I have a 36" standover clearance, but my pants all have a 32" inseam. Standover clearance is the important measurement on a bike, of course.
    Oops.......somehow I missed your post. Pffth.

    Yeah, sorry......I was giving a pants size inseam. Even then, a 30" inseam garment lends towards a loose leg. But, that's what I wear comfortably.

    I'm going to finish reading as I mentioned, measure my legs and all that, but thing is I just really like to stretch out on drop bars. Or, atleast have that option available on longer riding excursions. Just feels like on this thing I can't stretch out as much I'd like to without my seat bones beginning to push off the back of the saddle. So, maybe my predicament's not so much about "proper" fitment as what I like personally.

    I think the idea of a longer stem is really what I need to do. But, golly.....how common are 22.0mm stems with 100-110mm length?? Any idea? I'm just not seeing any right now save the ones I've mentioned. Hell, maybe I should just put some upright cruiser bars on it and call it a day...

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    Okay......so, I guess you guys/gals are right. I should stick with 170mm cranks. According to the three leg length methods, two out of three tell me my leg length is 34in's/86.36mm's. So, I guess my legs aren't that short......proportionally speaking....lol! Eh, I've just always considered them short.

    Anyway, yep......I'm going to blow off my bright idea, leave it as it is, put some different bars or stem (if I can find one at a more reasonable price), enjoy it for a bit, then flip it.

    Ah well.......my Peugeot will come 'round some day. Thanks for the input.

  20. #20
    Ride More seedsbelize's Avatar
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    Here is a chart for setback from B. Hinault's book and was used by all of Guimard's riders(Hinault, LeMond Fignon). I have always used this with good results. I would use a post that gets you in these ranges. The measurement is from the tip of the saddle nose to centre of BB measured horizontally.

    Inseam Saddle Setback
    75 to 78cm. 4 to 6cm.
    79 to 82cm. 5 to 7cm.
    83 to 86cm. 6 to 8cm.
    87 to 90cm. 7 to 9cm.


    Hope it helps!

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  21. #21
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    Not quite sure what's going on with those calculations, but I'll read the link and figure it all out later. Thanks.

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    Update........

    Went by the saddle adjustment protocol, but it didn't really make any difference. So, went back to the recyclery, found some thick platform pedals, installed the upright cruiser bars, and all in all found the comfort zone on this Pug. Still gonna flip it, but for now it's pretty fun.

    Thanks!

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