drum brake to disc brake

[VTRkemshell10...]

Hi,

im fairly new to the site and its been brill in finding helpful info but im trying to work out if i can upgrade my rear break from a drum to disc? is this possible and if it is how hard is it?

please help!!

thanks in advance

[Ditto]

Its probably possible but certaintly not feasible.

Firstly the gap in the swingarm would be different for a disc brake, and you would need mountings so maybe a new wheel. Then you would have to rig all the hydaulics up and mount the caliper aswell etc etc.

Added to that you use your front brake much more anyway so it would be quite pointless
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CG 125 > Bandit 600 > CBR 600 FY > Street Triple R

[neil.]

I wouldn't bother. Drum is fine as a rear brake on what I assume is a low powered bike? If anything, I find servicing a disc brake more annoying with all the seal replacements, mess and fiddlyness that goes with it. Drum brakes (not hydraulic ones!) are nice and simple, clean, grease, adjust, done!
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CBT February 2008 | A2 June 2008 | Yamaha YBR125 (written off) | Honda CBF125 (current)

[Noxious89123]

Properly adjusted, drum brakes can be quite good. The drums on the FS-1 are far better than the discs on the GS125...
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'06 Honda CBR125RW-6 ~ '00 Honda CBR600F-Y ~ '07 Honda CBR600RR-7 ~ Bikeless
'53 Ford Ka 1.3 ~ '03 Vauxhall Astra SRi 1.8 ~ '52 Vauxhall Astra SRi 2.2 ~ '53 Vauxhall Astra GSi

[Teflon-Mike]

The first question, & I'm surprised no-one has asked it (or am I missing something?) but, WHAT BIKE?!?!

If its an older TZR with drum brake and you want to fit the later disc brake TZR set-up, possibly a LOT easier than trying to re-engineer something that has never had a disc from scratch.

However; MORE to the point WHY?

Drums, properly serviced if OE Fit are normally more than adequete and have a few advantages; give more 'feel' for one, which is good if you are a newbie?

Next, if you paid heed in CBT, most of your braking comes from the front wheel; which if THAT is a disc should be preety powerful and more than up to the job.

And as 'upgrades' go, why elect to improve the back brake?

If MOST of your stopping power is coming from the front, most of the time, making the back better, wont be doing much if anything for you..... just mean you are more likely to lock up THAT much more easily in the e-stop........

THEN you have the consideration that such a modification IS a modification, and as such declareable to your insurance company....

FIRST question..... do you think they will like it?

I don't! They DO NOT like people fucking about with brakes. First they'll PRESUME that you have fucked about with them becouse you ride like an idiot, probably too fast and too far up other road users back-sides.......

THEN they'll presume that you are an incompitant mechanic, with no knowledge of the intricacies of vehicle design, and PRESUME that whatever you have done is ill considered and badly executed and LIKELY to make the machine more dangerouse than it is.

THEN they will weigh in the fact that the BRAKES are a SAFETY CRITICAL system of the motorcycle, and unlike say a luggage rack or fairing, WHEN this badly engineered modification fails, while being piloted by the speed-crazed incompetent, its going to wreak havoc and carnage on the roads.....

They will NOT like it ONE LITTLE BIT!

EVEN if thier presumptions are HUGELY unfair.... believe me, I worked for Lucas in the Advanced Technology Centre working on such things as 'smart-brakes'..... I once asked about fitting a brake-servo pump to my Series III Diesel Land-Rover (four wheel drive equivilent of a Honda C50), like more modern 'turbo-diesels'.... MUCH more sensible modification, by some-one who designed braking systems and they STILL didn't like the idea!

However, that asside, backing up, IF you are going to do anything, old rule of racing, BEFORE looking for MORE than standard, make sure you have all you should AS standard.

Basically, book may say that a ferrari can go 180mph, but an old clapped out one leaving plumes of smoke behind it probably wont beat an brand new Kia, simply becouse it end delivering all it should!

So, star with the basics; a good service. If you have disc brake up front, new fluid is often a WONDERFUL thing to treat it to. A new, and if you are feeling really flush, a braided hose, a brilliant improvement for little effort. As are softer pads.

BUT, remember when the brakes too good, you skid.

Limit of how much braking force you can apply depends on your tyres grip on the road, so decent tyres make a big difference too, and cheap hard compound comuter tyres even when new aren't exactly endowed with tenacity.

Suspension also effects your ability to brake, and again, new fork oil WILL make a big difference to how the bike stops.... think, first thing that happens when you brake is teh forks dive.... service the forks get some better damping going on, and the dive will be less and more of your braking force WILL get to the road earlier.

THEN you MIGHT start to think about other areas to 'improve'.....

Like servicing the rear drum properly. Again, greased pivots, a taut actuation rod, and decent shoes WILL make it work a heck of a lot better.

But, just that lot will almost certainly add up to much more braking than swapping rear drum to a disc, AND be more practical use, AND without changing anything from factory design NOTHING can be deemed a mod to worry your insurance co about.......
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