New stem fitting?

undermanager

Hi there

As I'm running out DIY jobs around the house, I'd like to change the stem on my road bike, from 120mm to 80mm or maybe 90mm, for a more upright position. I've looked at a few and like e.g. https://www.wiggle.co.uk/deda-zero-stem/

It's saying the handlebar clamp is 31.7mm. When I measure the thickest part of my bar, it's just under 29mm.

Anyone know if the 31.7mm is a maximum diameter, and if it should clamp down nicely onto a 29mm bar, or if the bar needs to be exactly 31.7mm?

Hope that makes sense!

Thanks for the help.

wongataa

The handlebar will need to measure 31.7mm where the stem meets it. It won't clamp down properly on a smaller diameter.

Wheelspinner

29mm would be an *extremely* rare diameter for a typical road bike handlebar.

The "old" standard back in the days of quill stems for road bikes was 26.0mm. Pretty much all the current crop are 31.7 (or 31.8 depending on manufacturer), with a few options in super-oversized 35mm.

What bike do you have that has this 29mm bar?

undermanager

Ignore my post!! I need a new brain / glasses.

Thanks

undermanager

So, once I'd used the vernier gauge rather than my eye and a ruler, it was 31.8mm !!

I changed over the stem from a 110mm generic stem to a 90mm Deda Element, which cost £14.00 and took 5 minutes to swap over, and went out for a spin today. My back aches a bit more as I've got older so last year I swapped out the drop bars for a flat bar on the Boardman Carbon Team bike to sit more upright, which was a fabulous move but not quite perfect still, but never got around to changing the stem. Silly me! Who would have thought that reducing the stem by just 20mm would have made the bike sooooo much better. I should have done it last year. The seating position is now perfect - no backache after two hours riding today. And the way the bike turns is far better as well, just about the perfect for the setup on the bike now. Happy days.

Hope this helps others thinking of doing the same.