1MM tyre clearnace too tight?

bmxboy10

Hi there, just got a new set of wheels built up and went for 25mm Conti tyres. Have now ascertained I literally have a minimum amount of clearance of 1mm (maybe less!) on the brake bridge. The bike rides ok but is this going to be a problem if I get muck or a stone in the gap? Its a CF frame!

Let me go and sit down.... :?

matt-h

I would say so.
You'll probably get more that 1mm tyre and wheel deflection on a climb

Matt

bmxboy10

Agree so I guess a 23mm tyre on the back is the thing to do?

k-dog

Definitely - but even that might be tight. You might want to try a few brands as they're not all the same size.

bmxboy10

What clearance do you need? Starting to realise the limitations of cf frames may consider going back to steel

lapavoni10

I would not say its a limitation of carbon frames as such, more to do with the frame build itself. What make is the frame...it seems extraordinarily tight clearance for what is a fairly standard tyre size.

marcusjb

Totally nothing to do with what it is built from. I had an old aluminium pinarello with about 2mm of clearance with a 23mm tyre! Thing climbed like a goat though. But every stone or bit of mud stuck to the tyre would clatter it's way through the frame. Leaves in autumn would get stuck all the time.

1mm is too tight really. You could experiment with different brands of tyre as everyone's 25mm is different, even from the same manufacturer (a 4000s sizes up bigger than the equivalent 4seasons).

I'd guess that, when clearances are that tight, even wheel rims might make a difference.

It is finally great to see manufacturers making frames with bigger clearances and it does seem that 25mm will be no problem on many modern framesets.

ai_1

solboy10 wrote:

What clearance do you need? Starting to realise the limitations of cf frames may consider going back to steel

What limitations of carbon are you refering to?
Surely not the clearance issue, it has nothing to do with the frame material?

markhewitt1978

1mm is not sufficient, that could get clogged with mud never mind small stones etc. I would think 5-10mm is what you should be looking for.

ugo.santalucia

markhewitt1978 wrote:

1mm is not sufficient, that could get clogged with mud never mind small stones etc. I would think 5-10mm is what you should be looking for.

In an ideal world... but clearly the frame is not designed to offer that kind of clearance. If a 25 gives you 1 mm, then a 23 will give you 3 mm, give or take. Conti tyres fit a bit large, while Vittoria tyres fit a bit narrower.

I suggest the OP measure the tyre with a Vernier, then you can assess what tyre you need.

ai_1

Is the clearance issue due to the height or width of the tyre or both?
While a 23mm will in theory give you 1mm more space either size of the tyre, I'm not sure how much the height will vary. It may be more than 1mm, it may not, and it may vary dramatically between brands, I don't know.

DeVlaeminck

I've had the same problems on a Look 585 with Michelin Pro4s, it would fit but as soon as I tried riding it any little bit of grit stuck to the tyre would rub on the frame or brake, like the OP I hadn't even considered 25mm tyres might be a problem given their increased popularity but I guess when the 585 was designed no pro would go bigger than a 23mm.

I didn't spend a lot of time investigating just stuck them on my other bike but having had a quick look I think it was a question of the height rather than the width - or at least the height was very very close it may be that the width was equally so.

drlodge

I've got about 2mm clearance on my Rourke between the rear tyre and the brake caliper arm in one spot. I've had no issue other than the understand of the caliper is somewhat scratched from crap getting in there.

The wheel is not going to flex in this direction, its just a question of crap possibly getting jammed in there. Personally I don't 1mm, 2mm or 5mm clearance is going to make much difference.

ai_1

DeVlaeminck wrote:

I've had the same problems on a Look 585 with Michelin Pro4s, it would fit but as soon as I tried riding it any little bit of grit stuck to the tyre would rub on the frame or brake, like the OP I hadn't even considered 25mm tyres might be a problem given their increased popularity but I guess when the 585 was designed no pro would go bigger than a 23mm....

The Michelin Pro 4 tyre in "25mm" size are reported to be especially big. They're more like a 28mm tyre in reality. You might be able to fit other 25mm tyres which are closer to an actual 25mm dimension such as a Continental or Vittoria tyre.

bmxboy10

Just to be clear I meant that the shape of the rear stays and brake bridge limit the ability to fit the tyres/wheels - not that CF has other limitiations but i do see this detail quite a lot on CF bikes. On my bike the brake bridge almost cacoons the rear tyre and despite taking loads of measurements and doing a mock up i still have no clearance. I will post a photo later. Interested to hear about the Rourke clearance as i would assume frames such as this would have no problem at all in accomodating 25mm tyres.

Off to Condor on friday so maybe i need a new frame not new tyres

ai_1

I think that is simply a choice by designers who are assuming you'll use narrower tyres and not a necessity imposed by the material. There are plenty carbon bikes with loads of clearance too. It pointlessly confuses the issue to suggest a link between CF and tyre clearance.

drlodge

My instructions to Rourke for my frame were "tyres 25c max" and I guess I could just squeeze 25c in there. But its close depending on how generous the tyres are. A little bit annoying since there's space on the caliper for the shoes to be lowered, which means the brake bridge could be a few mm higher.

ugo.santalucia

drlodge wrote:

My instructions to Rourke for my frame were "tyres 25c max" and I guess I could just squeeze 25c in there. But its close depending on how generous the tyres are. A little bit annoying since there's space on the caliper for the shoes to be lowered, which means the brake bridge could be a few mm higher.

Ah, the joy of bespoke... I think I have another 20 mm clearance when using 32 mm tyres with my Taiwanese TIG welded jobbo...

bmxboy10

Ai_1 wrote:

I think that is simply a choice by designers who are assuming you'll use narrower tyres and not a necessity imposed by the material. There are plenty carbon bikes with loads of clearance too. It pointlessly confuses the issue to suggest a link between CF and tyre clearance.

I am not confusing anything it's a fact in this case!

bmxboy10

ok so I swapped the conti 25s for my old Mavic tyres which are 23s and suddenly have mega clearance! Well about 4mm anyway....

For those who are interested the contis measured 26mm on the 23mm rim.

cycleclinic

Many tyres will come up smaller than contis like veloflex corsa try those. To little clearance it depends where the clearance issue is. My sannion has about 0.5mm clearance with 23mm GP4000s tyre on 25mm wide rims between the tyre and seat tube. It is a bit tight but the tyre is round and I won't ride it when its wet unless I change tyres. contis are known to be tall pick another brand which is not as tall.

birdie23

solboy10 wrote:

Ai_1 wrote:

I think that is simply a choice by designers who are assuming you'll use narrower tyres and not a necessity imposed by the material. There are plenty carbon bikes with loads of clearance too. It pointlessly confuses the issue to suggest a link between CF and tyre clearance.

I am not confusing anything it's a fact in this case!

A fact on this frame. Not a fact on carbon fibre frames in general.

I run 25mm Contis on my bike, probably about 1.5mm clearance. Not had any issues.

ai_1

solboy10 wrote:

Ai_1 wrote:

I think that is simply a choice by designers who are assuming you'll use narrower tyres and not a necessity imposed by the material. There are plenty carbon bikes with loads of clearance too. It pointlessly confuses the issue to suggest a link between CF and tyre clearance.

I am not confusing anything it's a fact in this case!

It's a fact you have limited clearance and that your bike is carbon. It's not a fact that you need to beware clearance on carbon bikes specifically as you implied: "Starting to realise the limitations of cf frames may consider going back to steel"

Anyway, it's a little off topic, so no point labouring the point any further. I just wouldn't like a beginner reading your comment and getting odd and false ideas about CF bikes.

Bar Shaker

I think the OP should buy a steel frame.

slowbike

Ai_1 wrote:

solboy10 wrote:

Ai_1 wrote:

I think that is simply a choice by designers who are assuming you'll use narrower tyres and not a necessity imposed by the material. There are plenty carbon bikes with loads of clearance too. It pointlessly confuses the issue to suggest a link between CF and tyre clearance.

I am not confusing anything it's a fact in this case!

It's a fact you have limited clearance and that your bike is carbon. It's not a fact that you need to beware clearance on carbon bikes specifically as you implied: "Starting to realise the limitations of cf frames may consider going back to steel"

Anyway, it's a little off topic, so no point labouring the point any further. I just wouldn't like a beginner reading your comment and getting odd and false ideas about CF bikes.

Hmm ... my CF frame and 23's are ok, 25's would be tight, wifes CF frame, 25's are ok, 28's would be tight ... can only be the fault of CF and nothing to do with the frame designer ... duh!

Those new to the field do read stupid comments like that and give them some weight - which is worrying - but the Solboy10 must believe it to be true too - makes you wonder what other weird notions he holds ...

DeVlaeminck

Ai_1 wrote:

DeVlaeminck wrote:

I've had the same problems on a Look 585 with Michelin Pro4s, it would fit but as soon as I tried riding it any little bit of grit stuck to the tyre would rub on the frame or brake, like the OP I hadn't even considered 25mm tyres might be a problem given their increased popularity but I guess when the 585 was designed no pro would go bigger than a 23mm....

The Michelin Pro 4 tyre in "25mm" size are reported to be especially big. They're more like a 28mm tyre in reality. You might be able to fit other 25mm tyres which are closer to an actual 25mm dimension such as a Continental or Vittoria tyre.

I can believe it - the Pro4s look massive - must admit they seem to roll pretty well on my Focus Cayo Evo though.

bmxboy10

Slowbike wrote:

Ai_1 wrote:

solboy10 wrote:

Ai_1 wrote:

I think that is simply a choice by designers who are assuming you'll use narrower tyres and not a necessity imposed by the material. There are plenty carbon bikes with loads of clearance too. It pointlessly confuses the issue to suggest a link between CF and tyre clearance.

I am not confusing anything it's a fact in this case!

It's a fact you have limited clearance and that your bike is carbon. It's not a fact that you need to beware clearance on carbon bikes specifically as you implied: "Starting to realise the limitations of cf frames may consider going back to steel"

Anyway, it's a little off topic, so no point labouring the point any further. I just wouldn't like a beginner reading your comment and getting odd and false ideas about CF bikes.

Hmm ... my CF frame and 23's are ok, 25's would be tight, wifes CF frame, 25's are ok, 28's would be tight ... can only be the fault of CF and nothing to do with the frame designer ... duh!

Those new to the field do read stupid comments like that and give them some weight - which is worrying - but the Solboy10 must believe it to be true too - makes you wonder what other weird notions he holds ...

Some very helpful comments thanks guys but.....

No weird notions here other than the fact that yet again on this forum someone is being castrated for making a slightly off the wall comment that happens to be true in this case and yet again the vultures are out seeking to out that person from the safety of homes behind their computers! IMO anyone how has over 4000 posts and is not a moderator probably needs to get out more.
Nothing stupid about my comment, it's based on fact according to my circumstances, bike, frame. I did not slate cf frames but the fact is a frame built using traditional materials and methods will generally be more versatile than the frame I have which is made of CF when it comes to tyre clearance.

bmxboy10

Bar Shaker wrote:

I think the OP should buy a steel frame.

I think you are right 8)

ai_1

solboy10 wrote:

Slowbike wrote:

Ai_1 wrote:

solboy10 wrote:

Ai_1 wrote:

I think that is simply a choice by designers who are assuming you'll use narrower tyres and not a necessity imposed by the material. There are plenty carbon bikes with loads of clearance too. It pointlessly confuses the issue to suggest a link between CF and tyre clearance.

I am not confusing anything it's a fact in this case!

It's a fact you have limited clearance and that your bike is carbon. It's not a fact that you need to beware clearance on carbon bikes specifically as you implied: "Starting to realise the limitations of cf frames may consider going back to steel"

Anyway, it's a little off topic, so no point labouring the point any further. I just wouldn't like a beginner reading your comment and getting odd and false ideas about CF bikes.

Hmm ... my CF frame and 23's are ok, 25's would be tight, wifes CF frame, 25's are ok, 28's would be tight ... can only be the fault of CF and nothing to do with the frame designer ... duh!

Those new to the field do read stupid comments like that and give them some weight - which is worrying - but the Solboy10 must believe it to be true too - makes you wonder what other weird notions he holds ...

Some very helpful comments thanks guys but.....

No weird notions here other than the fact that yet again on this forum someone is being castrated for making a slightly off the wall comment that happens to be true in this case and yet again the vultures are out seeking to out that person from the safety of homes behind their computers! IMO anyone how has over 4000 posts and is not a moderator probably needs to get out more.
Nothing stupid about my comment, it's based on fact according to my circumstances, bike, frame. I did not slate cf frames but the fact is a frame built using traditional materials and methods will generally be more versatile than the frame I have which is made of CF when it comes to tyre clearance.

Sorry, but this is simply silliness. You implied CF frames had "limitations" to do with clearance. This is rubbish as previously explained. In your last comment you yet again say "traditional materials" will be more versatile than the frame you have which is CF but gloss over the fact that the material is not the problem, the specific frame choice is. I don't appreciate your comments above which seem to be accusing myself or other posters of some sort of bullying. Nothing of the sort is involved. In my case at least, I've simply pointed out errors in what you've written. Have I been malicious in some way that I'm not aware of? :?
I've had plenty comments of mine criticised in the past. If those criticsims hold water, I'll accept them and change my position. If they don't, I'll do my best to rebutt them. That's how constructive discourse usually works!
As I said before, I wouldn't like to leave misinformation like this unchallenged as it can very easily be taken on board as gospel by beginners and passed on as fact (which it is not) and that does no-one any good. I would equally challenge someone saying stuff I knew to be wrong about anything else. I have no vested interest in this particular topic.

You have not rebutted my comments, you just keep coming back stating that your assertion is fact "in this case". Please re-read my earlier comment on this. I'm not contesting the issues you're currently having. I'm only contesting the INCORRECT extrapolation you've made and continue to make that this is a wider CF issue. It's not. If you wanted more clearance you could have had it with a steel bike, an alloy bike or a CF bike. Material has nothing to do with it. You simply bought the wrong bike. If clearance for 25mm tyres was important to you then you should have bought a bike that provided it. If you didn't know what you wanted when you got it, that's unfortunate but doesn't change the fact that use of carbon fibre as a frame material is not your real problem.
When I recently bought a new bike I spent a lot of time weighing up my options. I put together a list of potential purchases and one of the criteria I used to whittle down the list was the size tyres the frames could take. I wanted plenty clearance for 25mm and the possibility of going even bigger. So I bought a bike that can take up to 27mm and maybe 28mm. Simply put, I bought the bike I wanted.

bmxboy10

ai_1 look I apologise for my comments think I was having a bad day and perhaps I misread your initial threads. not saying you are bullying anyone let's draw a line on this one.

drlodge

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Line drawn :-)