Bike Sizing Issue

[Dansky]

My first roadie purchase (in 2008) was an entry-level aluminum Specialized Allez Sport and I've kept it as my "inclement weather bike," as well as for towing my young daughter in a Burley trailer. Because it has a triple crankset, the Allez was also my choice when I'd traveled out to Colorado for a bike tour in 2010, another of which is approaching this August.

The Allez is a 56cm, and in hindsight it seems likely that this puts the bike at the outer limit of the size range for a rider of my 6' height, depending on proportions. Note that my seat post stem is positioned quite high, something I never even noticed when I'd originally bought the bike. The fit feels good, so I haven't been inclined to worry about the bike size.

This is the issue. Whenever I've done hard sprints in a more aero position or been doing some steep climbing, I tend to scratch my knees on edges of the screws holding my stem to the headset. Not deep cuts, but definitely breaking the skin. A fellow at one of the local bike shops just suggested a piece of electrician's tape over the screws.

Comments and/or observations are welcome; I have come to consider this forum a great source of help and information.

 

[daveryanwyoming]

Well the fit question is hard to guess without seeing you on the bike but yeah a 56cm frame seems pretty small for someone 6' tall. You may be cramped up in the front end which could contribute to your issue with scraping your stem bolts.

But the easy answer if you really don't want to move to a larger frame is to buy a different stem or at least to grind down those stem bolts a bit. Most stems are built such that their bolts don't protrude out the far side when tightened down. That Bontrager stem you're running is a bit strange in the way the threaded end of the bolts stick out into space so far. Run a stem that doesn't do that and at least you'll save some knee scrapes. But really your knees shouldn't come anywhere near your stem or steering tube whether sprinting or not so that gets us back to an overly small frame.

I'd suspect you've got quite an upright and somewhat cramped position on your current bike. Sure maybe your torso and arms are proportionally short for your height but I'm guessing that's not the case. A short and upright position isn't necessarily bad for general riding around and touring but for someone sprinting fast in the drops it's not great.

Easy cheap knee saving fix, get rid of those protruding bolt threads. Longer term more expensive fix, have a good bike fitter check out your fit.

-Dave

 

[alfeng]

FYI. You can buy METRIC bolts from Home Depot (and, similar stores + from an LBS) ... I do NOT know if those bolts are as good as OR the same quality as OR better than the ones which are generally used for stems ... they are certainly adequate to hold water bottle cages & for other mundane purposes ...

• remove ONE
• take it to the store & buy a pair of shorter bolts
• put the "long" bolts in your tool box

BUT, before you go to any "hardware store" or to your LBS, check the bolts which are holding the face plate to the stem ... THOSE bolts may be shorter (i.e., the right length!!!) and perhaps the bolts were swapped by someone when the bike was "assembled" ...

• some brick-and-mortar bike shops are pretty casual about prepping a bike despite the fact that the consumer is paying a premium over a mail order bike for the prepping-and-handholding
• some LBS "Wrenches" are not as good as others

 

[Dansky]

Thanks for the responses thus far.
Alfeng, I will be checking the bolts from the faceplate for sure. Do you happen to know what torque all these bolts should be at, when I'm putting them back in?

 

[alfeng]

Originally Posted by Dansky .

Do you happen to know what torque all these bolts should be at, when I'm putting them back in?

Sorry, I do not know ...

 

[oldbobcat]

I'll bet you don't use the drops much.

It's pretty difficult to crush an aluminum steerer with a stem bolt, so I wouldn't worry. These bolts are for keeping the stem pointed in the right direction and maintaining proper side-load on the headset bearings, neither of which are high-stress applications. Firmly hand-tight should do it.

Here's a data point. Most manufacturers specify 4-5 Nm for carbon steerers, which should work fine for aluminum steerers, too. Grease threads but leave the interface dry and clean.

And here's a suggestion. On higher quality stems, the "ears" for the bolts are thicker to fully hide the bolt ends (and make a stronger clamp) and tapered to reduce contact with body parts, or at least make it less injurious. Then, as long as you're looking for a stem that won't lacerate your knees, you can find one with a higher angle, too, that will let you raise the handlebar a bit. That would let you level the top of the bar so you can use the drops once in a while. See your local dealer for options.

You can also make reaching down for a handlebar that's lower than the saddle more comfortable by sliding the saddle back a bit and lowering it a little bit less. You end up reaching farther forward, but the net effect improves because you have less weight on your arms.