Tight fit for guards

[robert17]

People, can anyone recommend a set of mudguards for my road bike. It is a Dolan Prefissio. As I hope you can see from the pictures, the space is tight. I have 25mm Continental tyres currently and would rather not drop to 23mm. Thank you. Robert.

[alexnharvey]

The minimum safe clearance to be aiming for is 10mm between guard and tyre. Given there is less than 10 mm from the low point to the tyre I think you do not have the room to run a full guard under the brakes there.

You could see this recent discussion of guards that have a gap at the brake bridge/crown as an alternative (e.g. sks raceblade long and giant defy mudguards).

viewtopic.php?f=5&t=142412

[robert17]

Thanks, but I'd like brake protection really.

[Brucey]

I've seen people run tighter clearances than that with mudguards (indeed I have run tighter myself in the distant past) but I have also seen some nasty accidents too. I'd think twice before using mudguards with clearances like that these days.

The danger is that a mudguard will get snarled up, jam and will stop the wheel. If this happens at the rear it is unlikely to kill you directly (although you might well skid and end up underneath a bus that way) but at the front if the mudguard jams you are in a world of pain; this kind of thing can kill you. The danger appears to be made worse if the front mudguard is set further away from the tyre at the bottom than under the fork crown; this tapered gap seems to encourage jamming.

If you want to mitigate the risk, make sure you have good stay releases, fit a 23mm front tyre, and/or use a mudguard which stops at the back of the fork crown and can be set further away from the tyre.

cheers

[amediasatex]

That's not a great deal of room to work with, Ive run with some very close clearances in the past but it's not ideal, to put it mildly, not only is the risk of getting something stuck and having an accident increased but with so little room you'll find rubbing and noises will be almost a certainty, and if you venture anywhere where there's any muck (rather than just water) you'll be clogged up in no time at all.

The biggest problem you'll face though is those brakes, they are some of the worst shape possible for fitting guards under due to the way the arms (especially the left arm) squeeze the guard when you pull the brake on. IME you need 5-10mm more clearance with those brakes than other models in order to position the guard such that it isn't pushed onto the tyre when you apply the brakes.

[mcshroom]

I suppose you could try crud road racer style flexible mudguards. Yes they do rub a bit, but they're designed to do that in order to allow tighter clearances to work.

[cycleruk]

The Dolan Preffisio was designed to run 28mm tyres and mudguards but with 58mm deep drop breaks.
I can't remember what I had on mine except I used Shimano brakes.
What are the brakes you are using as they look to be the limiting factor.?

[amediasatex]

The Dolan Preffisio was designed to run 28mm tyres and mudguards but with 58mm deep drop breaks.

Later ones might have been, early ones used standard* drop ~49mm brakes and there's plenty of stories of people struggling to run anything bigger than a 23mm with guards fitted.
Those brakes in the pic are Campagnolo (available in most of their groups at various points) 'skeleton' brakes with a listed 50mm max drop.

* depending on your age you may call them short

[Mick F]

My Mercian was designed to take mudguards. I specified it when I specced the frame in 1986.
In those days, narrow tyres were the norm, and I used them. Even when being dragged kicking and screaming into the new millennium, I was still using narrow tyres. 20mm Vittoria.
Now on 23mm Vittoria Rubino Pro ........... and they are marvellous. Been using them for years.
20mm were giving me the odd pinch puncture, so went up to 23mm, and since then, not one.

If I were to fit 25mm, I wouldn't be able to fit mudguards ............. but why would I want wider tyres?
I can't see the point of them. My bike is comfortable and springy and fast as it is.

[cycleruk]

My Mercian was designed to take mudguards. I specified it when I specced the frame in 1986.
In those days, narrow tyres were the norm, and I used them. Even when being dragged kicking and screaming into the new millennium, I was still using narrow tyres. 20mm Vittoria.
Now on 23mm Vittoria Rubino Pro ........... and they are marvellous. Been using them for years.
20mm were giving me the odd pinch puncture, so went up to 23mm, and since then, not one.

If I were to fit 25mm, I wouldn't be able to fit mudguards ............. but why would I want wider tyres?
I can't see the point of them. My bike is comfortable and springy and fast as it is.

Mick your bike is steel whereas the Preffisio is ali'. A much stiffer frame.
My Preffisio was a 2019 and it looks like the frame was altered to take larger tyres. I kept mine only about 9 months before selling it on.

[alexnharvey]

My Mercian was designed to take mudguards. I specified it when I specced the frame in 1986.
In those days, narrow tyres were the norm, and I used them. Even when being dragged kicking and screaming into the new millennium, I was still using narrow tyres. 20mm Vittoria.
Now on 23mm Vittoria Rubino Pro ........... and they are marvellous. Been using them for years.
20mm were giving me the odd pinch puncture, so went up to 23mm, and since then, not one.

If I were to fit 25mm, I wouldn't be able to fit mudguards ............. but why would I want wider tyres?
I can't see the point of them. My bike is comfortable and springy and fast as it is.

You and your Magic Mercian MickF.

I've got a Mercian and it still feels much nicer riding on a rough road surface 28mm tyres than the 23s it came with

[robert17]

The Dolan Preffisio was designed to run 28mm tyres and mudguards but with 58mm deep drop breaks.
I can't remember what I had on mine except I used Shimano brakes.
What are the brakes you are using as they look to be the limiting factor.?

They are Campagnolo Potenza.

[Brucey]

FWIW mudguards with a curved profile (eg SKS Bluemels) may be a better fit under your brakes than ones with a squarer profile (eg some other SKS models).

[edit; BTW if the brake block on the centre-pivoting arm is spaced further from the caliper arm, this can give a little more clearance for the mudguard by 'opening out' the brake arms. If the offset arm fouls the mudguard, often this can be adjusted using the centring screw, and swinging the whole caliper around the mounting bolt. This has the effect of moving the offset pivot up and down slightly, usually by enough to make moving the brake block in the slot necessary if you want the brake to work on the rim in the right way.]

cheers

[robert17]

Thank you. Would it not be odd to have a 23mm front and a 25mm rear?

[pwa]

Thank you. Would it not be odd to have a 23mm front and a 25mm rear?

It is quite common to have a wider tyre on the back. My wife has on her bike.