Dilberto

I just scored a Velocity Blunt SL 29er wheelset, for a great deal. I plan on running them with 700c x 25 tires tubed. Will there be any issues running high pressures(over 80psi) on such a wide(24mm) rim?

Burton

Hate to break it to you, but that tire / rim combo just ain't gonna happen. Your tire's going to pretty much be the equivalent of rim tape inside that size rim.

giantcfr1

Are you sure it's 24mm? I just googled and it says 20.80mm internal width.

See.. https://www.dirtragmag.com/reviews/re...nt-sl-wheelset

I am currently using 23mm tyres on my 700c SunRims, which I'm sure has a 20mm internal width. I am having no problems and have used this combo many many times on and off over the years, with never an issue. The trick is to ensure you have the tyres pumped up to the recommendation, and keep them at that pressure. If not, you could get pinch flats if you ride them low.

Burton

I think you're right. Missed the SL designation on the rims in the original post. The regular Blunts have a 28mm outside rim width vs the 25mm for the SL's.

But the minimum recommended tire size for that rim width is still 35c

Doohickie

Will 35s fit in your frame? I'm running 35s on my hybrid and have plenty of room.

fotooutdoors

Also, is your bike disc-braked? This is a disc-specific rim. Like others said, that is too narrow a tire for that rim. The narrowest I run on my A23's (23mm external, so 2mm narrower) is 28mm, and I have run those on dyads as well (24mm external width), which was pushing it. I wouldn't hesitate to run a 32mm tire on the blunt SL, but I'm not sure that I would drop to a 28 for that rim.

Dilberto

Yeah, its running hydraulic disc brakes. I can always go with a slightly wider tire. What really concerns me is the tire pressures.

Burton

Why would tire pressure concern you? A larger tire will carry a larger load with a lower pressure.

Dilberto

Because the tire I intend on using has a max pressure of 175psi(Vredestain Fortezza Tricomp 700c x 25).

Burton

So you're still convinced those tires will fit those rims? Subtract the 25mm width of the tire from the inside width of the rim (20.8mm) and you have about 4mm left. Divide by 2 and thats just enough to hook the bead on the rim - 2mm on each side.

Seriously - that's not a low profile tire - that's a NO PROFILE tire. Pressure isn't the issue - its having enough tire sticking up to drive on.

EDIT: OK - my apologies - I screwed up on the numbers. A 23c tire would be closer to 56mm in width which might leave you an approximate profile height of 10mm. Not something I'd drive in the street myself, but its your bike.

jsdavis

Why are you running such narrow tires on such a big wheel?

I get it that you maybe want some more speed out of your hybrid, but really get some 32 or 35 and inflate those to about 50-60 PSI and call it good. I ride on 42 at 45 PSI and my bike is plenty fast (for urban use).

If it's speed you're after, perhaps you should get a cross or road bike.

Acording to Sheldon Brown site, you want 13 to 17mm rims, internal width, for 25mm tire.
https://sheldonbrown.com/tire-sizing.html#width

jbchybridrider 

I understand the bike you want to build, the same as I've done a fast no compromise performance hybrid and riding it for the way you built it for. Forget the nanny poo safe recommendations and put the tires you got on your wheels and ride hard.
There going to be fine just run them at 100-110psi. My 29er wheels have 19mm internal width and I've ridden 2 years+ with 23mm tires, that leaves 2mm extra tire each side of the rim and I've never had a problem riding at max downhill speed and pushing through corners hard as I can.
I even remember having a leaking valve once on my front wheel and no pump about a year ago, I rode 10km's with the rim touching road but most of the time with just enough air to help the rim float a few millimeters most of the time. It wore most of the sidewall writing of my 23mm Schwalbe Ultremo's and the tire bead stayed planted to the rim, I still use the tube and tire today.

pierce

the narrowest tire *I'd* run on a rim would be 2-3mm bigger than the rims OD. OD is generally ID plus 4 to 6mm. on a 24mm OD rim, I wouldn't go under 28mm.

Velocity does promote using 23mm racing tires on their A23 (23mm OD) rim to get a tubular style ride.

re your pressures... I'm heavy so I'm running my pressures where the "X"s are. at 100 and 110 PSI, your 25mm tires are the "O"s. the weight is per wheel, your total weight + luggage + the bike might be a 55/45 split, something like that. I wanna get two bathroom scales and see if my guess is close.

jbchybridrider 

Pierce I think it's best to go by the internal rim width because that's where the bead is. Going by your theory on the outside I'm only running 1mm tire wider each side than the rim and I would consider that safe.

dynaryder

No way,I'd run that combo. You're going to have fun just getting the tires on. Made a similar mistake on my old 1X1 when I put 1.3" S-Licks on a set of Rhynolites.

I've got two BBU's;an '05 with narrow rims that came with 23's,and an '09 with wider rims that came with 28's. Guess which one rides better(and guess which one no longer wears the stock tires)?

The TdF roadies run skinny tires to shave weight and for aerodynamics. I think you'd really be happier with some 28-32mm sport rubber like Marathon Supremes or Randonneur Hypers.

dynaryder

Something else worth mentioning;just because the tires are marked 25mm,doesn't mean they are. They could be narrower,down to 23mm,which would make mounting them even harder.

Dilberto

Ok guys, let's end ALL the speculation and close this thread. I was able to install the 700c x 25 tire on the Velocity wheelset, pumped the tire up to 125psi and everything hooked-up fast and flush. In fact, the tire fits PERFECTLY....no tire stretch, no rim poke. The combo looks just like a wider tubular setup and the ride is outstanding; corners like it's a Ducati and accelerates well, thanks to the increased contact patch.

I say wider rim on a road/cyclocross bike is the remedy for skittish handling. The wider rims brings a whole new dimension of stability and razor cornering attributes....I'm now a BELIEVER!

Burton

Nope! Would appreciate if you hold this thread open and give a long term report after putting a few thousand miles on these and preferably swapping out with a buddy using a standard wheelset and tires.

I'll be the first one to apologize for mixing up 23 and 25 dimensions and somehow thinking that you wanted to run 23's on those rims, but as a fat tire fan myself - there are a few things I know for sure.

Using a wider tire at the same PSI doesn't change the contact patch area one bit - it just changes the PROFILE of the contact patch. So grip, both when accelerating and braking are unchanged. You may just like those tires.

Some of my buddies run 18c and 23c tires on road bikes while I run 25's. The difference on identical rims at identical pressures is a higher profile and more protection against pinch flats. The reality is that with a higher profile you can actually run slightly LOWER pressures and still have more comfort AND more pinch flat protection. But they do weigh more.

What you've done is used a wider rim and wider tire that resulted in a heavier wheelset than a narrower rim running 23c's , but with the same risk of pinch flats. If you're in an area where the risk of flats is low and the price you paid keeps you happy - thats really all that counts. I'm not that lucky and the streets in Montreal would make that combination a recipe for some expensive rim and spoke repairs. I not only see that regularly in the shop - I had the unfortunate opportunity to experience it firsthand - and I only weigh 155.

So I'm happy you're happy - just not convinced this is a radical improvement over other options.

pierce

actually, putting a 25mm tire on a wider rim is, from the standpoint of tire patch etc, just like riding a wider tire, but the sidewalls are shorter, so the tire will have less side to side wobble on turns and such. you'll probably find your tires are a little wider than 25mm now. if they are 25mm wide inflated onto a 13mm ID rim (really skinny race rim), their circumference from bead to bead is likely about 65mm (25mm diameter * Pi - 13mm). now if you put that same tire on a 20mm ID rim, its going to be more like 28mm ((65mm + 20mm)/pi)

so it stands to reason, you could use the same tire pressures you'd use on a 27 or 28mm tire, or more likely, something in between.

side_FX

I was actually wondering about the opposite. Can you put a 32x700 tire on an X-Caliber and create something like your own custom "Trek DS" sorta? I posted a similar question under the MTB section and I am only getting crickets.

pierce

how wide is that x-caliber rim? I would not run a tire skinnier than the outer width of the rim and generally prefer the tire to be a little wider.

ok, googled, x-caliber is the bike, and it uses "Bontrager Mustang 32-hole Tubeless Ready disc rims" but I can't find the specs on those.

I see some of the other trek/bontrager 29er stuff is 28mm wide, so yeah, a 32 would fit on those. it would be pretty stretched out, so it would ride almost like a tubular.

maizen1983

Sorry for such a late reply, but I've been thinking about the same thing. Here's the super helpful response I got from Travis at Velocity:

My question: What is the smallest tire size you would recommend for your Blunt SL rims?

His response: Thanks for contacting us. I would go all of the way down to a 25c tire on the Blunt SL. Please keep in mind that it is a light weight racing rim so while it will handle 80+ psi in a 25 or 28c tire, you will not want to put more than 60 psi in tires that are approaching the 2inch wide mark.

Straight from the horse's mouth.

-Matthew

Italia1970

cool

Dilberto

With Latex tubes = awesome.....feels like a freaking tubular. The heavy Velocity Blunt SL/XT hubs have since been replaced with Mavic Crossmax SLR 29 and the snappy ride with confidence-inspiring cornering is nothing short of spectacular. Close this thread...

Ginyu 83

good afternoon!

I'm a Spanish cyclist, I do not speak English, so I use google translator.

I looking for google, I found your post where you talk using 700x25 on mtb wheel covers.

What about work? any problem?

I want to use 700x25 in bontrager wheels RL MTB. It's possible? resist 8bar / 120psi pressure without breaking?

Thank you very much and greetings