t500 disc brakes question

[Tamadrmr26]

i want to convert my 72 t500 to disc brake. i know you can use the front end off a gt380, 500, 550, 750 but im having a hell of a time finding donor bike near me. i would prefer to find a full front end so that im not chasing down missing parts trying to assemble one.

if i were to buy all the parts from ebay or something and assemble one what would i need? the triples from one of these bikes will drop into the t500 frame i believe so i would need those, new bearings, forks, calipers, master cylinder, wheel/hub and discs, axle. would that be everything?

are there are any other bikes with a front end that will fit on my t500?

also, any tips such as, model years that wont match up or certain things to look out for while doing the swap let me know. any help is appreciated. this is a new bike for me and im trying to learn as much as i can about it before i start building it up.

if anyone has parts or has a lead on some near me (poughkeepsie, ny) let me know.

thank you! -erik

[advant63]

hi erik,
i believe the early small gs's may interchange as well. you'll have to confirm this yourself but that should broaden your options.

[johnakay]

the GT500 will bolt straight up!

[GT500Andy]

A good adjusted front drum brake is as good as a disk especially in the dry, is it worth all the bother to interchange them.
Andy

[johnakay]

there is no such thing as a good adjusted front drum brake.
they were always rubbish.disc is the way to go.
I would try and make a brembo caliper off an MZ fit.
brilliant little stopper.

[GT500Andy]

Yea, Brembo not the standard GT500 caliper I've got both and the stopping distances are marginal
Andy

[prmurat]

This should help you:
http://www.ohiocaferacers.com/OCRTubeSizes.pdf" onclick="window.open(this.href);return false;

Philippe

[Tamadrmr26]

nice. that chart is helpful. i just found a gt550 front end for $40. needs seals and break lines but that's no big deal. hows the performance of that caliper? i assume its the same as the gt500's. have any of you swapped on the brembo caliper?

[oldjapanesebikes]

i just found a gt550 front end for $40. needs seals and break lines but that's no big deal. hows the performance of that caliper? i assume its the same as the gt500's.

I'm not an expert, but I think you need to look at this as a package - its isn't just the calliper in play here, but also the rotor. And the rotor on these is not really the 'best' stopping material. I think you may find that just changing the calliper by itself may not make a huge difference if you are looking for current day, modern braking performance.

[Tamadrmr26]

yea, good point. i feel like the stock 550 brake will be fine for me. im just building this bike up to be a fun road bike, not a race machine.

[titan performance]

We are currently looking at braking options on a bike we are building. I agree, the standard rotor, or caliper, are never going to be the best option. It doesn't look to be too difficult to fit a bigger diameter modern rotor, and manufacture a bracket to mount a modern-ish caliper. unfortunately there is not room enough to fit an opposed piston caliper, as the back of it will foul the spokes, however, a twin pot nissin unit will fit readily...and this unit is easily available as it was used on a number of machines.

[oldjapanesebikes]

EBC still does list replacement rotors for the GT750. Possibly a bit dear, but they look nice No idea if they are the same metallurgy as the originals, but it would be interesting to ask. Do a search for EBP-MD3019RS and EBP-MD3019LS.

[tz375]

Nice looking disk. Is that the one they developed for Hammie's Chromeageddon? That plus SV calipers would do wonders for braking performance at a no too unreasonable cost.

[jabcb]

You might consider the following if you are looking to keep costs down, especially if you are concerned about brake performance when it rains.
Use modern aftermarket brake pads instead of old-tech NOS. EBC sells them.

For drilled rotor, get a 1980's GS rotor off of eBay. Not sure which one to get -- someone else should know.
Having at GT rotor drilled would somewhat more expensive.
Better yet, the EBC rotor oldjapanesebikes mentioned, but that's about $200.

For my GT250, I'm using a rear GS rotor purchased via eBay.
For my GT750, I had GT rotors surfaced & drilled by a company that offered the service via eBay.

Also worth considering are modern stainless brake lines instead of old-tech NOS.

[advant63]

hows the performance of that caliper?

Tamadrmr26,
i don't think the caliper is the issue with poor braking. the material that the disc is made from is the problem. the stainless steel is greasy and even worse when wet. they came with a warning sticker to that effect.
i have converted my 550 to dual disc using gs750 hydraulics and it is still a handful to slow down. katana rotors are the simplest cure.