Xiamen Carbon Speed 10 years anniversary special promotion

[c.etzo]

as reference, in my tt-x38 with rims 25 iw and 32mm gp 5000tlr they are 33mm real
and this is the space in the frame that claim 32 max tire

can't wait to receive the t1100 wheels

[biceryder]

32C clearance, or 32mm? There's no standard. Sometimes a seller will start saying 30C, then start saying 32C instead because it's what clients want to hear. My lt268 has plenty of clearance for 34mm, or more. Velobuild 177 claims to clear 32C but various users showed that it doesn't.
Best is to ask the factory for the CAD drawing and how much space there is between seat stays. That's what long teng sent me when I inquired before ordering my lt268.
In theory, 32C clearance should allow you to run 32C with a 33mm rim. For aero purposes, I'd suggest 30C on 33mm rim though, as the 30C will measure wider than 30 on a 33 rim.

Serge,  thank you for the clarifying information.  I mixed up clearance with wheel width.  I’m leaning towards the CS-R01.  Peter sent measurements of the chainstay which put it around 38mm at the narrowest.  By my estimates that would give the frame 2.5mm (5mm total) on either side to clear a 33mm OW wheel.  I like to go as wide as I can to support 30-32mm tires.  I’m just unsure if 2.5mm is enough clearance or pushing the limits of what the frame can support.

[Macedingle]

Are you not susposed to run a 28c tire on 24 internal rims?

[Sakizashi]

Are you not susposed to run a 28c tire on 24 internal rims?

ETRTO guidance and UCI rules would say no—so as of mid last season this would be an illegal combination for racing on the basis of safety. While blowoffs are the catastrophic failure, the more common issue of too wide of a rim is riding on the sidewall and getting more punctures.

The C on tire sizes has nothing to do with width—it’s the designation for the bead seat diameter (BSD) of the rim (622mm). The format you all are seeing are looking at is referring to the different dimensions of the rim. 700 is a size designation that is supposed to the OD of the system at some arbitrary tire size that was historically used. The only place where this is still relevant is for 650b vs. 650c. Tires are specified in the format of [size designation]x[width][BSD].

Actual tire width for road tires is specified on a different rim width thats sort of standard and sort of manufacturer dependent. Most 28s are specified for a 19mm or 21mm IW rim for example and most 32s are to a 23mm or 24mm IW rim. 34+ is usually true to size on a 25mm IW rim.

To make matters worse there are two different ISO standards for tire clearance to the frame. 6mm is the off-road standard that gets used on a lot of allroad and gravel bikes. Some manufacturers (e.g., Trek) use 6mm on their road bikes too. 4mm is the road standard that also sometimes gets used for allroad and gravel bikes.

If you want to make sure a tire / rim fits your bike the best thing to do is measure or get a dimensioned drawing of your bike frame to compare. Most fork and frame manufacturers can provide this if its not in the listing.

TLDR: for road widths 23mm IW width rims give you the most options. 24mm-25mm is good too as it allows you to fit 30s. Measure your bike and the tires. You probably want 4mm of clearance on all sides of the tire and similar to the rims.

[volan]

Yeah, I don't really understand why many (?) people here are going for those 26 mm inner width rims for road use with narrow tires. ETRTO recommendations don't exist for nothing. You can usually go a bit further than recommended, but it's a bit of a gamble.

Unless you want to to exclusively run 32+ mm tires, don't get those rims!

That said, it would be great to see something between 21 mm and 26 mm rim width. Something like 23 or 24 mm would be pretty versatile.

Well, it's hard not to see the direction of the industry. With Enve ses line, their 25/33 width, they recommend 27c as a minimum and they literally state "aero optimized tr tyre size". With the trend towards wider tyres, and having 105% aero "rule" (and it really does mean something), it's really hard to ignore that.

Kudos to Serge_K for introducing me this trend, and recommending to go wider. I went initially with 28 ow, but told Peter if it's ok to change to wider option, and thankfully he approved. Cost difference is about 20$ per rim, even less.

On the same tangent, but a bit different topic. Chinese industry follows the trend. After all, all major brands ship their blueprints long before the product arrives to market. And they ship them blueprints to manufacturing plants, guess where? Well, China ...And don't you think that once they have their eyes on those blueprints, they won't use the opportunity to jump ahead of the rest? Meaning they'll have the similar product ready to be manufactured as soon it gets the hype from that major brand?

I bought my carbonda fm936 xc full-sus 2y ago. The frame was from 2019. And the geometry is still SPOT ON with the trend. If you go to 2019. and see the geo numbers on all xc bikes, you see huge difference with some noname chinese oem's that somehow made so progressive frame years before it was the "thing".

They follow the trends, and use simple logic to get advantage every way they can. It may be not so moral from some perspective, but damn, we can get up-to-date products with decent enough quality for a really good bargain. Take my money.

[planet_sammy]

I don't know if I missed it, what is the maximum rider weight with carbon spokes and 21mm inner width of the tires?

[ry]

I've been considering the 26mm IW wheels with the intention of using minimum 32c tires but just looked up the ETRTO and the min size recommended for 26mm IW is 35c tires. 

Is it best to follow this guidance? If so then I guess I'd go for the narrower wheels but have to expect that'll result in a hit in aero performance.

[toxin]

32c will be fine, will probably inflate beyond 33 anyway

[lazvask14]

Then get the new uni rims from yuanan that are 23iw and 32 external

Not seeing uni rims on their site with 23iw and 32 external. Are these not listed yet?

[Serge_K]

Not seeing uni rims on their site with 23iw and 32 external. Are these not listed yet?

their website is pretty useless. Best to liaise w Peter on whatsapp, or via the forum. I never even look at their website anymore.

[BeR]

their website is pretty useless. Best to liaise w Peter on whatsapp, or via the forum. I never even look at their website anymore.

They have a new website but under construction :

https://www.xmcarbonspeed.cc/

[Nkearb]

That website lists the tire compatibility for the 26mm internal wheel

5, Compatible for 700*23C-43C tire (tubeless ready)

 What does ETRTO know anyways im gonna go ahead and setup 23c tubeless

[volan]

I've been considering the 26mm IW wheels with the intention of using minimum 32c tires but just looked up the ETRTO and the min size recommended for 26mm IW is 35c tires. 

Is it best to follow this guidance? If so then I guess I'd go for the narrower wheels but have to expect that'll result in a hit in aero performance.

If ENVE recommends 27c tyre as best aero optimized for 25iw, then for sure you can run 30c on 26iw... That's my logic anyways.

edit: just to put a good word for Peter here on forum... this was his message the other day:

"Hi Ivo,

This is the tracking number by UPS: XXXXXXX

BTW, I paid extra $48 on shipping because you are from remote area   But it is OK, hope you like our products

Best Regards,
Peter"

I don't need to say much more. Of course I payed the man the difference. But the fact he didn't even ask for it is... hands down.

[Sakizashi]

If ENVE recommends 27c tyre as best aero optimized for 25iw, then for sure you can run 30c on 26iw... That's my logic anyways.

ENVE has a specific list of tires tested to work specifically with their rims. There is no generalizable design principle here that can be applied to other wheels as the problem lies with the tire geometry, rim geometry, and the tire-rim interface

There are two sets of somewhat conflicting general recommendations. There are the ETRTO-based charts from the tire makers earlier in the thread, but also their general recommendation that there be a minimum of 5mm between the marked tire width and the rim's inner width. Many brands, including ENVE, Zipp, and Hunt, do not like either recommendation. Ultimately, those in favor (Continental, Mavic, etc.) won out, and the UCI adopted the 5mm recommendation as a rule. This forced teams like UAE to use the 30mm GP5000 S TR and move away from the 28mm TT TR tire.

This became an issue because of a bunch of high-profile tire blowoffs, largely on Zipp wheels, that resulted in injury to pro riders. However, there are also a lot of anecdotal blowoffs of other brands as well that you can find by searching other forums.

At the least, I would follow the 5mm rule on this one and run 32mm tires, as the consequences of a blowoff are the same as rolling a tubular tire off the wheel--if it's on the front, you will likely crash. I plan to follow both the tire maker charts and the 5mm rule, as I like not crashing.