25/28mm Tyres on Ksyrium Elite SL Wheels

richard36

Hi

Would appreciate some advice (done a search but can't anything relevant to my question)

I have a bike from Rose where everything is carbon - frame, seatpost, handlebars - and I have Ksyrium Elite SL wheels. I have Continental GP 4000s 23 mm tyres. I live in rural Dumfries & Galloway where in the main the roads are not smooth. However, I generally don't find the ride is too bumpy or uncomfortable.

I'm wondering whether to get some 25/28 mm tyres to see if there is any noticeable difference with the ride. I've read loads of posts/articles on various sites and the one thing that might mean it isn't a good idea is because the rims on the Elites are 15 mm. I've read that having such narrow rims might negate any benefit of having 25 mm tyres.

Can anyone tell me whether it would be a good idea to move up to 25/28 mm tyres or not?

Many thanks

ai_1

Richard36 wrote:

Hi

Would appreciate some advice (done a search but can't anything relevant to my question)

I have a bike from Rose where everything is carbon - frame, seatpost, handlebars - and I have Ksyrium Elite SL wheels. I have Continental GP 4000s 23 mm tyres. I live in rural Dumfries & Galloway where in the main the roads are not smooth. However, I generally don't find the ride is too bumpy or uncomfortable.

I'm wondering whether to get some 25/28 mm tyres to see if there is any noticeable difference with the ride. I've read loads of posts/articles on various sites and the one thing that might mean it isn't a good idea is because the rims on the Elites are 15 mm. I've read that having such narrow rims might negate any benefit of having 25 mm tyres.

Can anyone tell me whether it would be a good idea to move up to 25/28 mm tyres or not?

Many thanks

If you're happy with the ride then there's no NEED to change but you may find a softer tyre gives you a better ride. It will certainly provide more cushioning from bumps and rough surfaces. The reason to use larger tyres is so that you can drop the pressure and still support your weight without risking pinch punctures.
Narrower rims do not prevent you using wider tyres. Wider rims will provide a more semi-circular profile rather than a 3/4 circle which should be a little more stable and since the rim is wider it will increase the volume encapsulated by the tyre a little further. Neither is a reason to prevent you from using 25mm tyres on 15mm rims. If you think you'd like a smoother ride, you're not obsessed with rock hard tyres and your frame provides enough clearance then go for it.

richard36

Thanks for the reply.

Whilst at present the ride isn't uncomfortable it would be nice to have a smoother ride. It was for that reason I was going to go with 25 mm but as said in the OP I had read somewhere that having narrow rims i.e. something like 15 mm, would mean negate the benefits of wider tyres.

Cheers

ai_1

Richard36 wrote:

Thanks for the reply.

Whilst at present the ride isn't uncomfortable it would be nice to have a smoother ride. It was for that reason I was going to go with 25 mm but as said in the OP I had read somewhere that having narrow rims i.e. something like 15 mm, would mean negate the benefits of wider tyres.

Cheers

That's not true. 25mm on 15mm rims will be fine and will give you a smoother ride if you drop the pressure a little.

richard36

Thanks Ai_1 - much appreciated

ai_1

Incidentally, I use Ksyrium Elites with 25mm Michelin Pro4 SC which gives a lovely ride. The bike came with these wheels shod with 25mm Yksion Pro tyres which were also very nice and since Mavic pairs these together they clearly think 25mm + Mavic Ksyrium Elites is not a problem!

richard36

Hopefully Ai_1 or someone else can answer my 2nd question!

I've now bought some Continental GP 4000S II 25c through Wiggle. I'm 66kg and wondering what the best psi would be. I don't race just enjoying cycling around rural Galloway. Want to strike a balance between a comfy ride and a fast ride.

Thanks

bob6397

Try 90 as a start point - the rear should be 5-10% higher in pressure than the front, and the pressure is entirely subjective. I am 56kg and 5'10" and I run my 23mm front at around 110 psi and the back around 115.. I prefer a firmer ride (The roads round here are so poor I just try to avoid pinch flats..)

bob6397

richard36

Thanks

ai_1

At a weight of 66kg I think 25mm tyres would be fine at 75psi front and 85psi rear for a comfy ride. The best pressure for you is largely subjective. You can go as low as you want until you start getting pinch punctures or as high as the tyres allow but you you may get rattled about rather a lot. I like them comfy but still firm enough not to squirm when I get out of the saddle to sprint or to push hard on a climb.
I weigh about 86kg and typically use about 95psi back and 80psi front. I've been know to go a little higher when I'll be on good smooth roads or lower if I expect poor surface quality and bumps...not that I regularly change pressure between rides or anything.

Bobbinogs

Ai_1 wrote:

At a weight of 66kg I think 25mm tyres would be fine at 75psi front and 85psi rear for a comfy ride. The best pressure for you is largely subjective. You can go as low as you want until you start getting pinch punctures or as high as the tyres allow but you you may get rattled about rather a lot. I like them comfy but still firm enough not to squirm when I get out of the saddle to sprint or to push hard on a climb.
I weigh about 86kg and typically use about 95psi back and 80psi front. I've been know to go a little higher when I'll be on good smooth roads or lower if I expect poor surface quality and bumps...not that I regularly change pressure between rides or anything.

Yepp, I am 65kg (or was before getting injured a couple of weeks ago) and ride 25mm tyres at 75F/80R. The roads around here are not too bad though. Interestingly, a club ride went down a really poor quality lane recently with quite a few potholes and several of us got pinchflats (or even double pinchflats), irrespective of who was riding what PSI. Hence, probably not worth obsessing too much about a few PSI here or there because if you really tw@t a pothole then you will puncture whatever. I personally think 75PSI is about as low as I would want to go for other reasons like ensuring a secure tyre beading (I have tried 70PSI but wasn't too happy about tyre deflection when climbing, could be just in the mind though).

richard36

Those are great replies - many thanks

dodgy

Have you measured your frame to see if 25 / 28mm tyres will fit? I have 25mm (Pro Race 4 which are known for being on the wide side) on my Rose, but it's fag paper clearances, the slightest build up of dirt and you can hear them rubbing.