Hi,

I bought a new bike, but it comes with a super wide MTB riser bar. I'm used to 40cm wide bullhorns and riding with such a wide bar will be very uncomfortable.
I'm thinking about using a trekking bar on this new bike, but the narrowest I could find so far was a 58cm wide bar.

Anyone knows a trekking bar between 40 and 50cm?

Mine are 58cm. I can't imagine a set that was only 40cm, it is already somewhat tight with controls.

Trekking bars that are 58cm wide will have controls that are probably 30-40cm apart. Your main grip area will be mostly where you like(40cm).
The remaining 18cm is equally split on each side and is measured at the widest point of the bends.

At about 55cm I have an ITM freetime* , and at 57cm another ITM product..

Importing from Europe you can get the Modolo Dumbo handlebars https://www.modolo.it/products/trekk...umbo-standard/

then, width is an adjustment choice..

But the typical bars coming from Pac Rim sources are under $30..



* standard component pick on a NL made Trekking bike , Koga WTR. in 04, I bought 9 years ago..





....

AFAIK all trekking bars are wider than you specify. Even Modolo Dumbo with adjustable width narrows down to minimum 54cm c-t-c (unless you hack it).

Here's an alternative to a bullhorn. Take an inexpensive 3-5 degree bend MTB flat bar, cut ends off (with hack saw or tubing cutter) to desired width, and add ~12cm long bar-ends. This will approximate the geometry of a bullhorn bar while enabling use of existing controls, at relatively low cost. Note the size bar needed for compatibility with your stem (25.4 or 31.8mm). A bar which tapers to the diameter required for MTB lever/shifter mounting (22.2mm diameter) in the shortest distance is preferable as it permits narrower control location, narrower overall bar width, and may leave room for accessory mounting. 25.4mm bars are usually better in this regard, as 31.8 bars have a larger center bulge which takes 9-15cm to reduce diameter.

Google "flat bar with bar ends", then click images tab, and you'll see dozens of examples.

I was thinking exactly that, if I could not find a propper trekking bar. Cut the one that comes with the bike and using a bar-end with it.
Still not my favorite option, because I lose the curve on the corners (and that's where I rest my hand 80% of the time), but if I can't find any other option...
Humpert ergotec would be perfect for me, but it is still 60cm wide.

I've seen these at REI, they always intrigued me: https://www.rei.com/product/884447/e...CABEgI_nfD_BwE

Looks like a good option. Thanks.

I have a pair of these on some riser bars that I cut to a width I prefer, and it's a pretty good combo. I also ride a butterfly barred bike, regular cheap North American sourced ones, and they work well also. Yes they seem wide a bit, but they are worth trying out, especially at 25-30 dollars and you don't even have to recable usually. A longer stem generally is needed, and find some old bar tape and double wrap them, then play with angles and live with them for a while.

you could hack your current mtb bar and add bar ends,
or get a vintage zoom (54 or 56 cm) on ebay.

Zoom Brahma Handlebar