Hi to all, does anyone have any experience of the HMB stainless steel floating brake discs? My front original cast iron discs are warped and I was looking to maybe upgrade to stainless steel replacement discs, I see HMB offer a straight replacement stainless steel discs for my Le Mans as well as full floating replacement front stainless steel discs. If I’m going to change to new stainless steel discs I’m thinking I should bite the bullet and buy the floating discs.
Has anyone installed the HMB stainless steel disks and/or the full floating stainless steel discs? I would really like to hear your opinions
I have bought a pair for my 750S replica but have not fitted them yet. They are not floating and I have powder coated the disc carrier and the center of the discs black so they look more like the original ones. The contact area of the discs are unpainted, but I guess to make them really authentic they should be rusty!
The HMB floating discs come with the centre carriers anodised black to achieve a close to original look, my front discs are shot so there’s no better time for an upgrade, stainless discs should be better than the originals and in theory floating stainless discs even better but it’s not a cheap option and I would feel better if I could get an opinion from somebody who has converted to stainless discs or floating stainless steel discs.
I have a pair on my Spada. The originals were worn and warped and with pattern replacements being of questionable quality I opted to buy the HMB discs, along with sintered pads.
Installation is easy enough but I did need slightly longer bolts as the carrier is a bit thicker.
They have been on for 2 seasons now and work well, but last year they developed a groaning noise when coming to a stop. I have taken the pads and pins out and cleaned everything but not really ridden it much since so can’t say if it’s fixed.
PS - I bought them post-Brexit so HMB deducted VAT at their end, and I fully expected to pay UK tax/duty but the parcel landed on my doorstep with no problem.
stainless has less friction than cast iron so as a material hypothetically isn’t as efficient for slowing down, main reason to use on motorcycles is less rust. having said that brake technology and metallurgy has improved a huge amount since the 1980s to cope with more powerful bikes than a le mans
I’ve seen people complaining on a suzuki forum that sintered pads ruined their disks, but on a modern enough bike i would expect them to be stainless, not sure what went wrong there
I’ve had stainless discs on all my bikes except my Le Mans since the 1990’s I never had a problem with stainless steel discs on any of my bikes, modern bike brakes are unbelievably powerful using stainless steel disks so I think if there are properly engineered stainless steel disks on the Le Mans should be a suitable upgrade, getting suitable brake pads might be an issue though, I’ll have to look into that, suggestions appreciated
Preventing rust is nice but not my main reason for considering stainless steel floating discs, cast iron solid discs are well known to suffer from disc warping (my discs are warped) floating discs can expand and contract better and are much less prone to warping, they are also lighter than the original cast iron discs
I have fitted the HMB discs to my Spada but have yet to try them on the road. One issue I had was that the bobbins rubbed against the inside of the gork leg and centering of the wheel was more critical (not just a case of shimming the calipers). I had to file a couple of mm off the fork leg where the casting is thickest. I also put a 0.5mm on the right side of the wheel spindle. This may not be the same on the LeMans as the off sets are different anyway. I have to say they are remarkably light compared to the cast disc and Michael at HMB is a good guy to deal with. Ps if you are considering the rear disc, its just as light with a replaceable rotor but it isnt a floater.
Thanks Mr P, I see on the HMB website they say “new design”, there are no more issues like floaters colliding with brake pads, fork legs, etc. so hopefully they have solved the clearance problems. I’ll email them and ask about the fitment issues as well as the need for longer bolts that Ranton Rambler mentioned. I want to get the best out of the original braking system that I can without altering the base bike as it’s totally original, so although I really like the idea of floating discs I wouldn’t want to take a file to the sliders to get them to fit, I think I would just change the disc rotors to a set of HMB’s stainless ones.
All good information, now I have a bunch of questions for HMB, I will give feedback as and when I get an answer from them…
I contacted Michael at HMB with regard to fitment issues with the floating discs and the need for longer mounting bolts, this was his reply.
“This is a straight swap. As our floaters are flush with the rotor surface, there are no issues here.”
“ Screws must be a little longer, if you have stock wheels, then:
I think I’m going to jump in and buy a pair of stainless steel floating discs, longer bolt kit and pads from HMB. I’m about to send the front forks off for an upgrade which could take a month or longer, once I get everything together I give some feedback.
It’s been a long wait for the Maxton forks upgrade but finally I was able to assemble the front end end and the backend and therefore I can now provide the promised feedback on the HMB stainless steel floating front discs as well as the HMB stainless steel rear disc which I decided to purchase as well. Firstly the “new design” front discs fitted without the need for any modifications whatsoever other than using the longer mounting bolts, the rear disc likewise fitted perfectly, no modifications required. Secondly weight, the front disc’s weight was pretty much the same as the old cast iron disc’s but the rear disc was significantly lighter (approximately a kilogram lighter) Overall the quality of the disc’s is superb, however I am yet to test the brakes as I still have a few more things to do before my Le mans is ready for a road test.
Looking good Don. These look like the same version as I fitted to my Spada. I have now put it on the road and they work very well. However, initially I had a problem with one of the front discs which wasn’t floating. I hadn’t realised this until my rep Simon D pointed it out. In a previous life hed designed floating brakes for trains! Anyway stripped the rotor and found one of the spring washers had been caught under the circlip. Put it back together and it was fine.
Hi Mr P. Those discs look nice against the gold colour
I see you are running the Bridgestone BT46. I’ve yet to test my new brakes or my new BT46’s, hopefully in maybe 2 weeks or so my Le mans will be ready for a test run. What’s your opinion of the BT46 tyres? I’ve run Bridgestone tyres on my other bikes, but never on my Guzzi.
Cheers, Don.
Im very pleased with them. Id say theyre better than the BT45s but the Spada has been off the road for a few years so its subjective. The bike handles well and gives a lot of confidence. Haven’t taken it out in a downpour yet. BTW I run 120 on the rear, same when I had BT45s on.
Final thoughts. Initially the new stainless steel discs and pads were scary, like braking with discs made of ice, it was suggested to me to “ drag the brakes a little” to bed them in quickly I didn’t like that idea at all, what if I ended up with overheated and warped new expensive discs, no thank you. I decided to just take it very cautiously and hopefully everything would bed in eventually. At about 250 kilometres the brakes started to get some feel to them and I could see the discs were starting to bed in, at about 500-600 kilometres I was happy that the brakes were definitely feeling as good or maybe a little better than the cast iron discs, but since the the brakes have continued to improve, the brakes have done over 1000 kilometres now and are fully bedded in and the feel and bite is quite a bit better than the iron discs, overall although not cheap a very worthwhile upgrade. The Bridgestone BT46 I’m not yet convinced, grip seems okay but the bike seem to be more skittish on the white lines than it was before. The Maxton front fork upgrade is to say the least a revelation, the transformation from 40+ year old tech to todays top end spec is astonishing.
Hopefully this information is useful to some other Guzzi rider out there.
I didn’t like that idea at all, what if I ended up with overheated and warped new expensive discs, no thank you. I decided to just take it very cautiously and hopefully everything would bed in eventually. At about 250 kilometres the brakes started to get some feel to them and I could see the discs were starting to bed in, at about 500-600 kilometres I was happy that the brakes were definitely feeling as good or maybe a little better than the cast iron discs, but since the the brakes have continued to improve, the brakes have done over 1000 kilometres now and are fully bedded in and the feel and bite is quite a bit better than the iron discs, overall although not cheap a very worthwhile upgrade. The Bridgestone BT46 I’m not yet convinced, grip seems okay but the bike seem to be more skittish on the white lines than it was before. The Maxton front fork upgrade is to say the least a revelation, the transformation from 40+ year old tech to todays top end spec is astonishing.