Hi All,

I currently have a mountain bike which has the following wheels: Alex XD Elite double wall 29" - 32H, Pin Joint, Formula QR hubs.

I am not using this as a mountain bike and want to convert it into more of a commuter bike. I want to put slicks on it, but I don't know how narrow I can go considering it currently has 2.1 mountain bike tires.

Any advice?

Regards,

DSL1970

It has 19mm inner and 25 mm outer. The narrowest I would run is 25mm but personally I would run at least 32mm

29'er wheels are the same ERD as 700c road wheels, so '700c' road or hybrid tires would work.
ALEX list the rim as a 19mm width, so you could concievably go as small as a 28mm road tire.

I'd stick with something in the 35mm-38mm range, which should give you a faster tire, but still have enough volume to absorb bumps, debris, and the occasional curb-hop.

You may want to stay with a larger tire,but just a smooth tread like a Schwalbe Big Apple 2.1" I find that urban riding is a lot like fast trail work, and the big volume helps shake off obstacles and road hazards.

I concur with the recommendations not to go too narrow. Look for a light flexible tire, and you should be pleasantly surprised at the improvement in ride.

My two cents...medium to flat slicks.

Meaty, Beaty, Big & Bouncy...

Fatter tires tend to have lower rolling resistance and lower pressure.

I have some 60mm slicks that have similar rolling resistance (~10 watts) as my 23mm road race tires.

I've gone as low as ~40mm, but below that you are just dropping the bottom bracket real low and getting a stiff ride. Its not faster. I've used 25mm tires on my mountain bike, but it was just ugly and inefficient.

I would recommend some 45mm gravel tires (Panaracer or Schwalbe make some good ones).

When I converted my 29er I ran 32mm Schwalbe Marathon Supremes. Seemed like a good compromise. 35mm still felt like knobbies to me. 28mm just didn't look right on my wheels.

All great advice here.

You wheels will be able to safely handle 700X28 or so tires without any issue. You get to choose the model of tire and the width. Think about the roads and trails you will be riding on - are they rough and potholed or smooth and newly paved? If smooth you can easily get tires on the narrow end of the scale, which will make your bike a bit lighter and the higher pressures will make for a livelier ride. If the roads are rough or potholed, fatter tires will still roll nice and fast but can be run at lower pressure to soften the ride and still prevent pinch flats and rim damage. Is this in an area with lots of debris and possible flat-tire-causers? Then choose flat-resistant tires like Schwalbe GreenGuard or Specialized Flak Jacket (every manufacturer calls their flat protection something different, but all do essentially the same thing). If you are less concerned about punctures you could opt for less robust tires, which will tend to feel lighter and will roll a bit easier (not so easy that it makes up for having to stop to fix a flat, though).

If I were you I would start with some 700X45 or 700x50 (approx. 2" wide) tires - something like this: https://www.schwalbetires.com/bike_t...big_apple_plus

The great thing about tires is that they are a wear item, so if you decide the tires you have aren't ideal, you can be motivated to ride more to wear them out so you have a reason to change them!

I'm in a similar position, looking to switch to narrower tires for my 29er. Currently has Kenda SmallBlock 8 front and Slant Six rear 700x54. While my Performance Access XCL 9r has plenty of room for wider, I really don't ride offroad enough to warrant knobbies. But I do want some reasonable gravel tires, rather than slicks. Thinking 32 to 42 is a good size. I have been tubeless with the current set up, but went tubed after the bike sat for a couple years. Just haven't pulled that trigger with other bikes needing attention. First world, N+1 problems...

Get the fattest, lowish resistance tires you can get. , On my drop bar trek 830 mtb i run a 26x1.9 riddler in the back and a 26x1.95 fasttrak in front for an 11 mile commute and it can handle all the irregular surfaces and curb hopping required to make the trip.

If you are commuting you don’t want or even need too skinny a tire, especially on a mtb. I would look at 32-35 mm width, and something with some tread and built in flat protection. Plenty of faster tires which are not slicks. Maybe even a tire liner in the tire. I would get all kinds of flats from radial tire wires before my Mr Tuffy liners, bear in mind I am running all road gear.
Figuring your gear for commuting is a learning experience and trial and error. Look at the commuting forum, a lot is there to help you figure it out. People there are riding anything from fixies to mountain to full on road bikes. I have commuted steadily now for a year and a half, off and on for 6 years prior to that. Enjoy!