# Bicycle Mechanics - Mudguards

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View Full Version : Mudguards

yannis
05-20-12, 06:43 PM
Which should be the ideal space between tire and fender?
Is a 10mm space enough?

yannis
05-20-12, 07:05 PM
Another relative question. I have read that is difficult, but not impossible, to fit a fender under a short reach brake. Will a short reach brake fit on a frame hosting 40mm tires, or larger, and fenders?

yannis
05-20-12, 08:09 PM
Thinking about it a little more...

10mm the distance between the hole for the brake's bolt and the bottom of the frame (where the "wheel hosting space" starts)
+5mm (minimum) clearance
-----------
Total 15mm

The short reach brakes have a maximum reach of 59mm without exception

Removing what above calculated are remaining 44mm. These 44mm are the space where the wheel (tire and rim) is inside the brake callipers.
Removing 8-10mm more (the rim's surface for the pads), remaining 34-36mm.
So, a short reach brake with maximum reach of 59mm could host a 34-36mm wide tire (or a smaller tire and fender).

Am I wrong?

HillRider
05-20-12, 08:15 PM
10 mm between the tire and the inside of the fender is plenty. 5 mm clearance is marginal if any mud or debris gets between the tire and the fender. BTW "short reach' brakes have a amximum extension of typically 47-49 mm. "Long reach" have an maximum extension of 57 -59 mm. I expect neither will clear a 40 mm tire.

yannis
05-20-12, 08:43 PM
BTW "short reach' brakes have a amximum extension of typically 47-49 mm..
This should be an ultra short reach brake calliper.

Andrew R Stewart
05-20-12, 08:59 PM
You can do the math/diagraming easily enough. But there's a reason that cantis/linears are used on large profiled tires, espicially with fenders. The leverage goes down with the longer caliper arms needed to clear the big tires and fenders. But then you probably already knew this. Andy.

HillRider
05-21-12, 10:07 AM
This should be an ultra short reach brake calliper.
Not in today's terminology.

fietsbob
05-21-12, 10:36 AM
People have fabricated mounts for mudguards,
that cover the tire every where but
where the clearance under the brake is insufficient.

yannis
05-21-12, 12:13 PM
You can do the math/diagraming easily enough. But there's a reason that cantis/linears are used on large profiled tires, espicially with fenders. The leverage goes down with the longer caliper arms needed to clear the big tires and fenders. But then you probably already knew this. Andy.

Do you mean that short reach brakes have not the sufficient power to stop wider rims?
I have heard about it and also something similar about the length and the shape of the brake levers, but I am not an expert...
Could you explain me with more details the relationship between rim width and caliper arm length?

HillRider
05-21-12, 03:51 PM
Short reach brakes have plenty of power to stop wider rims. What they may not have is sufficient room under them to clear the wider, taller tires that normally accompany wider rims.

Andrew R Stewart
05-21-12, 11:26 PM
As hillrider said. Andy