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Fiddle brakes


Diesel_90
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Im looking into fitting fiddle brakes on to the back of my latest trialer project. what type of cylinders do i need and what are your views on fiddle brakes

Thanks in advance

I use them and love them!!!

As to the fitment! well that depends, if you have 4 wheel brakes or only brake on the front axle on the foot peddle! If you only brake on the front, then you can use a early 110 front caliper's on the rear, and plumb in a set of series or similar clutch m/cylinder's! But if you use all four brake's then you can use the Milner inline lever's.....but i would still change the rear caliper's over to 110 front's.

I use them on my Class 1 Muddler and i've just fitted a sett to my 90 tray back. Fit them and i bet you'll wonder how you drove with out them!

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I use them and love them!!!

Same here, i had a set on my AWDC class 1 single seater trialer, i had a pair of series clutch master cylinders plumbed to raingie front calipers on the rear axle and that worked quite well.

I have seen a trialer with front fiddles, which to me seems dangerous (ripping steering wheel out of hands...), but i never saw it in action. I knew two people who ran the milner levers and swore by them, also knew a guy who put servo operated master cylinders, which seems like a gd idea, but he was forever distroying axles 'cause he had to rev the engine to create enuff vacume, and obviously locking one wheel whilst revving is a recipe for disaster!

There is a knack to using them, apply the fiddle brake first to lock the wheel before turning the steering wheel, this helps in turning the steering wheel, and also slews the back end arround, rather than just dragging the locked wheel.

The other alternative to fiddles and 4 wheel brakes on the pedal is to make up another bracket to hold a second caliper onto the rear axle, and leave the standard set up alone.

I will be putting a set onto my S3 challenge vehicle.

From memory tho, (talking to a frendly MOT man) for MOT purposes, a vehicles main braking system should not be altered. Therefore adding a second pair of calipers to the axle should keep MOT man and any nosy plod's off your case...

Hope this helps

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I've contemplated fitting line locks to a vehicle - no extra calipers etc. you just push the pedal and lock pressure into whichever caliper you want to stay put. The drag racing boys use them to lock the front wheels when they warm the rear tyres up B) and you can get electric ones for not many pennies.

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Couldn't you use RRC 4 pot front calipers (or is this why 90 fronts was suggsted)?

Then you have one piston for the foot brakes and one for the fiddle brake?

No, i tried that, the trouble is each piston on its own isnt quite enough to lock the wheel, i ended up plumbing both pistons and that works great.

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Thanks for the info :)

Im going to go the route of using series clutch cylinders but would disco rear calipers be good enough or would i need to fit something bigger e.g disco front calipers?

A wise man told me that rear calipers are not man enough to lock the wheel (as Tony said above.) You need four pot calipers to get enough braking effort.

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No, i tried that, the trouble is each piston on its own isnt quite enough to lock the wheel, i ended up plumbing both pistons and that works great.

Ah good info cheers that will save me doing that then :D

Watching motors with fiddles it looks really easy to lock em up, but I guess with big diameter grippy tyres it all makes sense.

What happens if you air down the tyres is there a high risk of losing a tyre?

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Ah good info cheers that will save me doing that then :D

Watching motors with fiddles it looks really easy to lock em up, but I guess with big diameter grippy tyres it all makes sense.

What happens if you air down the tyres is there a high risk of losing a tyre?

In our club, we used to run 7.50 dumper tyres and 235/85 grizzlys at between 10 and 20psi on standard landie and rangie rims and no one i know of popped a tyre while using fiddles.

im sure its possible tho

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It appears to be true that you need 4 pot calipers with simple clutch master cylinders, but it just comes down to the mechanical advantage.

There are several alternatives to this which achieve the same end.

1. Use longer levers

2. Use servo assist

3. Use master cylinders with a smaller bore

4. use a pressure multiplier (just a hydraulic ram. feed pressure into the end without the rod and you get higher pressure out of the end with the rod (as it has a smaller volume)

5. Feed from a higher pressure hydraulic source - such as PAS pump

Si

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