# F4s & 25mm tyres



## brawlo (Jun 16, 2011)

Hi guys,

For various reasons I've started looking at an F4 as my new bike. After so many false starts with a new bike purchase, I'm finally in a position to have a guaranteed purchase.

So my question is for fitting 25mm Conti 4000 tyres to the F4. Previously I had my sights set on a Cervelo and I found that the tyres wouldn't fit. That wasn't the deal breaker, but I have changed my focus for other reasons. So now the primary reason for the Felts is the frame size. There's not a lot of choice out there for a big guy, and when you're trying to buy locally, then there's even less!

I'm currently riding velocity A23 rims with Conti 4000 tyres and the ride is good. Will they fit on a new rig?


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## sandiegosteve (Mar 29, 2004)

Eyeballing my F4 with Michelin 23mm Race Pro 4's, I think there is plenty of room. I haven't tried 25mm though.


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## jrhz06 (May 15, 2011)

I have Conti 4000s 25mm on my F5 so I would think that they should fit on the F4.


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## brawlo (Jun 16, 2011)

Well, not sure where my post went to from last week, but thanks for that @jrhz06. That's exactly the info I needed. From all reports the Contis run taller than most other 25mm tyres. A 2012 F4 looks to be coming into my possession very soon.


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## brawlo (Jun 16, 2011)

Just a quick follow on from this post for anyone in the future. I WAS running my Conti GP4000 tyres up until a week ago. I had only done about 200km on the new bike and took the rear off to put a different cassette on. In doing so I noticed that the tyres seem to have rubbed a small groove into the chainstays. They only had about 1mm of play to begin with, but it seems I flex the frame enough to cause a fair amount of rubbing to have done the damage in only 200km. Thank god I found it. Now all I need now is for someone to say the groove was already there and I'll be happier with the frame.

Also a couple of disclaimers, I'm 115kg and sprint on the track so it seems I'm flexing the frame a bit. Also I run Velocity A23 rims, so I presume the tyres are a bit wider in profile because of them.


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## bwbishop (Sep 17, 2011)

How is your wheel laced? It may be the wheel flexing and not the fault of the frame or tire.


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## brawlo (Jun 16, 2011)

Laced 3x 32 spoke. I had no problems with them in my older aluminium frame


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## bwbishop (Sep 17, 2011)

*Re: F4s &amp; 25mm tyres*

They could have been hitting the aluminum frame, but you might not have noticed because rubber won't wear down aluminum like it does carbon.


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## brawlo (Jun 16, 2011)

It still leaves marks, of which there aren't any on the aluminium roadie. I had this happen on my first aluminium track frame as well. Pretty decent skid marks were left inside those chainstays. I've since gone to a carbon frame on the track and after finding this, I checked it out too, and no problems there. Only a fraction more clearance on the track frame with 32 spoke 3X aerohead rims. The frame flexes a bit, I can tell when compared to riding my track bike, but still a fair bit stiffer than my old road bike. About the only thing I can think of now is to increase the spoke tension on the wheels to stiffen them up a little more and keep a close watch for more wear in the chainstays.


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## jrhz06 (May 15, 2011)

I've got about 1000 miles on mine and just checked it. Not a mark, but I'm using the stock wheels.


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## jmorgan (Apr 13, 2012)

A23 are not that stiff of a rim, you could try lacing some Kinlin XC279 rims which are stiffer, also make sure your hub is not loose. You are a big dude at 115 kg, I think it could easily be the rim.


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## brawlo (Jun 16, 2011)

Yeah those Kinlin rims have just come up on my radar for a new wheelset. I've sought out a build on those from a wheelbuilder over here, still waiting for a reply with it being the festive season and all.

Can any F3/4/5 owners comment if there is an indentation on the chainstays next to where the tyres sit. Fair enough it may have rubbed, but thinking about it, I can't see it doing so much damage in only 200km.


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