2 bolt vs 4 bolt stem - is there a difference
 

Hi

I'm looking at a new stem - maybe an Easton EC90, which has two bolts to clamp the handlebars while many other manufacturers have four bolt stems. Does it really make much difference if you have a two bolt stem?

davida

From what I have heard, it doesn't make a difference. I would be fine with either. I think the nicest stem available is made by Thompson and they only have two bolts. I currently have a Ritchey and it has four bolts.

Edit: The stems with four bolts have small bolts and the stems with two bolts have larger bolts. As long as you have them torqued down, you will be fine.

None other than looks.

I'm all for the extra baby bolts.

I heard some people state that the 2 bolt ones would potentially have more 'flex' to the handlebars. But I cant see how that would be true if they were torqued correctly.

bryceman - i guess theoretically the idea is that two clamping points is better than one. imagine trying to hold a stick horizontal with one hand in the middle vs. with two hands - much easier with two hands, since it is secured at two points rather than one, so there's really no way for it to rotate. but i bet there's really no significant difference with stems and handlebars because the distance between the bolts is so small relative to the bar length.

the only other concern i can think of would be that with carbon bars, 4 bolts might distribute clamping force over a larger area, making damage to the bar less likely...but again, there's probably no real significant difference.

According to Thomson's website their 2 bolt design is just as strong torsionally as other's four bolt designs but weighs less. Thomson has a lot of credibility since they make probably the best seat post on the market.

http://bikethomson.com/products/stems/elite-x2/

It probably wouldn't matter as much since the face plate takes the pressure and distributes it across the bars. As long as the bolts can be torqued down to the proper amount, the bars should be held the same regardless if it is two bolts or four bolts.

I think its actually easier to properly torque a 2 bolt stem vs a 4 bolt. Trying to tighten all of them evenly, a little bit at a time... going back and forth. It much easier doing this with 2 bolts, just worrying about one axis (symmetry top/bottom) versus doing a 4 bolt pattern and worrying about 2 axis of motion (top/bottom and left/right)

Which is the reason, some handlebar mmanufacturers give for saying not to use their carbon bars with 4 bolt stems.

i have a sort of related question. I've got a 4 bolt stem that came with steel bolts. I've got 4 aluminum bolts that actually fit... would this be a "no no"? i've never heard of a stem coming with aluminum bolts and i'm not sure if i'd feel safe as they wouldn't be nearly as strong as steel (or ti). should i be looking around for Ti bolts if i want to lighten the stem up?

So, the answer is that it doesn't make a difference.

Yes, Ti is always best.

It's still not hard to properly torque a four bolt stem.

interesting. guess i was mistaken.