Author Topic: Xiamen Carbon Speed rims/wheels  (Read 651217 times)

toxin

Re: Xiamen Carbon Speed 10 years anniversary special promotion
« Reply #240 on: January 09, 2025, 03:38:43 PM »
Saying it breaks down completely is even more facetious than saying if don't abide to the 0.1mil you may as well run box sections.

So you think brr drum tests are meaningless because 'nOt ReEl LiFe'.  ;D

Im saying this because I've run cfd simulations on various rim shapes with various tyre sizes. 105 just has no meaning

Sakizashi

Re: Xiamen Carbon Speed 10 years anniversary special promotion
« Reply #241 on: January 09, 2025, 05:17:23 PM »
I think its a good idea to verify dimensions. There seem to be a pretty wide tolerance on rims and tires that I have seen. This is on the higher side of the small sample size I have measured, but not insane. Lets also remember that your calipers are not perfect either.

Regarding 105--this "rule" was christened in an era of different wheel shapes, narrower tires, and rim brakes. It's also often misused in forums in reverse of what it was intended for. It was to help you select the best tires for a given wheel, not the other way round. Its been abused and misused and isn't relevant anymore.

Rim profiles matter. The fastest U-shaped profiles for a front wheel can be a watt or more faster, particularly at shallow yaws, but the air detaches so much sooner that they aren't used as much anymore. I think the Hunt Sub50 paper documents this pretty well when they cover all the rim shapes they tested. If I remember correctly and did the math right at 48kph the fastest profile suffered detachment a few degrees earlier, but was like 1.5w faster. Is it worth it to optimize at that level? I guess it depends on you, but following the rule of 105 on a rim that's not the right shape for that rule to apply wont get you very far.

Lotnik

Re: Xiamen Carbon Speed 10 years anniversary special promotion
« Reply #242 on: January 10, 2025, 04:47:44 AM »
And new combo wheelset 20/20H carbon spokes hubs built with  D50CU-33 T1100 rims UD paintless was just released, around 1180+/-20g/pair
How does lacing pattern looks like on that wheels? Front and rear?

Nkearb

  • Guest
Re: Xiamen Carbon Speed 10 years anniversary special promotion
« Reply #243 on: January 10, 2025, 10:01:45 AM »
Im saying this because I've run cfd simulations on various rim shapes with various tyre sizes. 105 just has no meaning

That great that you disproved a BS 25yo wind tunnel test with an even more BS CFD analysis.


I actually skip wind tunnel testing and CFD analysis, I acquire a rim profile in a .jpg file format and scanning with my eyes I am able to calculate the aero performance of a particular tire-rim transition with a 100% margin of error

patliean1

Re: Xiamen Carbon Speed 10 years anniversary special promotion
« Reply #244 on: January 10, 2025, 08:32:57 PM »
A quick teaser. More details later...
Thank you Peter!!

c.etzo

Re: Xiamen Carbon Speed 10 years anniversary special promotion
« Reply #245 on: January 11, 2025, 03:32:58 AM »
build my wheels with gp5000 S TR 32mm and they are 34-35mm real

KaiDeus

Re: Xiamen Carbon Speed 10 years anniversary special promotion
« Reply #246 on: January 11, 2025, 10:52:44 AM »
Got my first ride in, 2h30 Z2 at 0°C and wet roads, so can't say anything about the finer riding characteristics, but overall I like the wheels very much. Running 28mm front and 30 rear, which measure 29mm and 31mm respectively. Both tyres at 4bar/58psi, setup tubeless. That is the 50mm deep 29 rim outer 22mm inner width btw.

First impression is that the wheels strike a good balance of stiffness and compliance. The ride is firm, but not harsh, road vibrations are kept in check. Obviously that combination of tyre width and inner rim width doesn't provide a plushy ride, but they feel non fatiguing to me with my setup. Road conditions here are pretty bad and I made an effort to not avoid road cracks etc.

Cross wind stability is alright. Large close passing cars do create a small tuck, but I also tend to have a light grip on my handlebars. Steering always corrected itself and I didn't feel the need to preemptively brace myself for any passing car.

Daviddavieboy

Re: Xiamen Carbon Speed 10 years anniversary special promotion
« Reply #247 on: January 11, 2025, 04:18:45 PM »
build my wheels with gp5000 S TR 32mm and they are 34-35mm real

 Not surprised the tire ballooned up with that wheel/tire combo. Def outside recommendations. Are you using tubes or going tubeless ?
I have a hope until someone can prove otherwise.

c.etzo

Re: Xiamen Carbon Speed 10 years anniversary special promotion
« Reply #248 on: January 12, 2025, 12:52:12 AM »
Not surprised the tire ballooned up with that wheel/tire combo. Def outside recommendations. Are you using tubes or going tubeless ?
Tubeless

ry

Re: Xiamen Carbon Speed 10 years anniversary special promotion
« Reply #249 on: January 12, 2025, 05:41:52 PM »
That great that you disproved a BS 25yo wind tunnel test with an even more BS CFD analysis.


I actually skip wind tunnel testing and CFD analysis, I acquire a rim profile in a .jpg file format and scanning with my eyes I am able to calculate the aero performance of a particular tire-rim transition with a 100% margin of error

What specifically makes you say his particular cfd analysis is bs? I'm interested in seeing the details.  Maybe he has deep expertise and validation data at his disposal. Maybe not. idk.

ry

Re: Xiamen Carbon Speed 10 years anniversary special promotion
« Reply #250 on: January 12, 2025, 05:47:37 PM »
Not surprised the tire ballooned up with that wheel/tire combo. Def outside recommendations. Are you using tubes or going tubeless ?

Are you suggesting this is an issue or a good thing or NBD?  I need to decide what tires to run on mine.

ry

Re: Xiamen Carbon Speed 10 years anniversary special promotion
« Reply #251 on: January 12, 2025, 06:09:20 PM »
Just a quick update on my order.

D50CU-33 w/new in-house straight through hubs & 5mm width carbon spokes are ready to ship. 

They look great in the picture and the weight is impressive.

Thanks all for your help and of course to Peter for being so patient and helpful with me as well as for making these wheels available.
« Last Edit: January 12, 2025, 08:06:45 PM by ry »

patliean1

Re: Xiamen Carbon Speed 10 years anniversary special promotion
« Reply #252 on: January 12, 2025, 07:52:24 PM »
Just a quick update on my order.

D50CU-33 w/new in-house straight through hubs & 5mm width carbon spokes are ready to ship. 

Thanks all for your help and of course to Peter for being so patient and helpful with me as well as for making these wheels available.

Incredible. I went with the same rims and hubs, but different/thinner carbon spokes.

Trilobite

Re: Xiamen Carbon Speed 10 years anniversary special promotion
« Reply #253 on: January 13, 2025, 09:43:06 AM »
They look so great. Hope I receive my D50CU-33 wheels soon too  ;D

patto3

Re: Xiamen Carbon Speed 10 years anniversary special promotion
« Reply #254 on: January 13, 2025, 08:06:44 PM »
Incredible. I went with the same rims and hubs, but different/thinner carbon spokes.

Excited to hear your review Pat! You've got a wealth of knowledge with testing wheels, and these currently represent the best value/specs (ultra lightweight, carbon spoke, wide int/ext) for money by FAR!