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25mm or 30mm Rims with 2.35 tires


Furbz
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So i am in the market for some new MTB wheels.

 

the riding i am doing currently is some XC riding (the occasional race like 947 MTB), general marathon riding and stage races like Sani/W2W etc.

i live in JHB.

85-90% of my mtb rides are comparable to Cradlemoon yellow route and surrounding outrides.

 

the question here is 25mm or 30mm internal width when paired to 2.35 or maybe 2.25 tires.

 

my gut says the 25mm would be just fine and my head says 30mm is more progressive for the industry.

 

thoughts?

Edited by Furbz
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So i am in the market for some new MTB wheels.

 

the riding i am doing currently is some XC riding (the occasional race like 947 MTB), general marathon riding and stage races like Sani/W2W etc.

i live in JHB.

85-90% of my mtb rides are comparable to Cradlemoon yellow route and surrounding outrides.

 

the question here is 25mm or 30mm internal width when paired to 2.35 or maybe 2.25 tires.

 

my gut says the 25mm would be just fine and my head says 30mm is more progressive for the industry.

 

thoughts?

maybe consider MODIFYING your message heading? Whilst the 25mm/30mm is correct, the 2.35mm mm is very wrong! inches, not mm, I suspect!

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So i am in the market for some new MTB wheels.

 

the riding i am doing currently is some XC riding (the occasional race like 947 MTB), general marathon riding and stage races like Sani/W2W etc.

i live in JHB.

85-90% of my mtb rides are comparable to Cradlemoon yellow route and surrounding outrides.

 

the question here is 25mm or 30mm internal width when paired to 2.35 or maybe 2.25 tires.

 

my gut says the 25mm would be just fine and my head says 30mm is more progressive for the industry.

 

thoughts?

I've been riding 2.35 tires on 30mm ID rims the past 9 months and it made a noticeable difference.  Really enjoying the lower pressures.

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I have 2.35’s on 21mm rims. Would like a bit wider. If it was me, choosing between 25 and 30mm I would probably go 25mm. Anything wider than 2.35 I would take 30mm rims.

 

yep its feels to me the magical number is more like 27.5mm 

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post-177909-0-49388000-1613724607_thumb.jpg

 

The major things to keep in mind is how the tire profile is affected by the internal width of the time. 

 

Too narrow ID and you create the balloon tyre which will affect the overall contact patch between the tyre and trail. The round profile will also affect how stable the tyre is. Will it squirm because the beads are squeezed too close together. 

 

Too wide ID and you create a square tyre which will affect the side knob grip when leaning the bike over for cornering. I think you might be more susceptible to pinching the sidewall as well. I can't remember 100%. 

 

post-177909-0-57584800-1613725043_thumb.png

 

The graph above should give you an idea of the ID vs tyre width grip / squirm.

 

#notadoctor but you can also reference this thread : https://community.bikehub.co.za/topic/179705-rims-width-affect-on-tyre-width/

post-177909-0-83642700-1613724893_thumb.jpg

Edited by Steady Spin
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I run 2.4's on 22mm ID rims. They work perfectly. No pinch flats despite being hammered and because the rims are narrow they are built strong and are still light. I also run 2.5s on 29mm ID trims.

 

IMO, based on some empirical experience, wide rims are overrated. Wider means heavier so they make the rims weaker to cancel this out.  Coupled to this, you are more likely to end up with damaged rims and a pinch flat because the rim is wider and less protected by the overlapping tyre. 

 

I think 25mm rims with up to 2.5 tyres (depending on tread pattern to some extent) is probably the sweet spot, but I haven't been able to put this to the test yet.

Edited by Headshot
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I run 2.5's on 23mm id rims and i fall in the heavy category 115kg plus range (have not weighed for a while) i ride on 2bar pressure and have not had any problems and i enjoy giving it down hill over rocks etc. Grip is good, especially now that i replaced those old Hans Damph's.

 

Now running Maxis Aggressors and Assegai's very happy so far.

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In my experience, wider is better. Currently running Bontrager Kovee Pro 30 mm rims with 2.35 tires. It's a treat. 

 

Was running 30 mm, went back to 26 mm that came on a new bike, and didn't like it. I found ways to roll the tire off the rim going through corners, tires didn't feel as well seated and stable as with 30's. Just not as confidence inspiring. Therefore back to the 30's for me after having experience on both. 

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Every year the industry shows us a new study that even wider is even better... Im running 30mm id rims with 2.35 front and 2.25 back, and they're absolutely awesome. Planning to go a little narrower on the rear for mud clearance, but honestly no wierd feelings, only planted, solid, fantastic riding experience.

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So i am in the market for some new MTB wheels.

 

the riding i am doing currently is some XC riding (the occasional race like 947 MTB), general marathon riding and stage races like Sani/W2W etc.

i live in JHB.

85-90% of my mtb rides are comparable to Cradlemoon yellow route and surrounding outrides.

 

the question here is 25mm or 30mm internal width when paired to 2.35 or maybe 2.25 tires.

 

my gut says the 25mm would be just fine and my head says 30mm is more progressive for the industry.

 

thoughts?

If the Frame is wide enough at the back you can run 30 mm at the back.

If the Frame is narrow you will get Mud Wearing out the Chainstays

If the Frame is narrow then 30 mm in front and 20-25 mm at the back.

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Interesting to hear everyone's perspective on this. I currently run a set of Cobalt 2's which probably has an internal width of 22 or so along with 2.35 front and rear. It took some getting used to (my bike felt very twitchy) but now it's ok I guess. I have always wanted a nice wide set of wheels. I do think it will make a difference in the riding experience.

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I have had both.

 

I honestly don't notice a difference.

 

I ride my tires slightly harder in summer to avoid the exposed rocks on the blown out trails and slightly softer in winter.

 

I notice way more if my fork or shock needs air or a rebound tweak than I do rim width.

 

I put this down to the fact that I don't run super low pressures as I really can't be arsed to replace dinged rims in the name of 'performance'.

 

For 99% of us, the equipment we ride isn't the bottleneck.

 

Get wide rims if you need to replace your wheels, but I don't think there is a noticeable performance enhancement for most hackers worth thousands of rand if you already have a decent set of wheels.

 

That being said, I don't own a set of MTB wheels narrower than 30mm ID, but this is purely due to the fact that I have recently built up a new bike and used the Lyne wheels, while my SS has some sexy Spank 345's, which I purchased as the modern 'trends' made them available at a reasonable price point

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I'm running 34mm internal width rims on my 5" travel trail bike, my tyres vary from 2.35 to 2.6 depending on my own mood more than anything... I can certainly feel the difference in the different tyre widths and the difference between running same tyres on a narrower rim. What is interesting is that there is virtually no difference in my segment times up or downhill, or in my ride average speeds...

 

Here's a slightly more rigorous test:

 

https://www.pinkbike.com/news/rim-widths-comparison-test-mountain-bike.html

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