McDuugle Posted June 4, 2017 Share Posted June 4, 2017 I know that the min thickness of both the front and the rear rotors is 4.5mm, however does anyone know the thickness of the brand new rotors for the front and the rear before they go into use? Just curious to see what the staring pint is. Also in respects to the rear rotor, does anyone have experience or advice regarding the cheap ones on ebay like this: http://www.ebay.com/itm/Rear-Brake-Disc-Rotor-BMW-R850GS-1996-2000-R850R-1994-2006-R850RT-1996-2001-C-US-/112421750235?fits=Model%3AR1100RT&hash=item1a2cdbc5db:g:tfEAAOSww9xZKcHM&vxp=mtr Are rotors for the R1100RT compatible with any other models, asking so I can increase my search radius. Link to comment
Selden Posted June 4, 2017 Share Posted June 4, 2017 I bought a Chinese rear rotor off eBay last year, and it has worked out just fine. Re the front rotors, mine were grossly under minimum thickness, and I replace them with a set of EBC rotors with bobbins pre-installed, sourced from Beener Boneyard. ~20,000 miles since which a required more time than swapping out the roors. Link to comment
McDuugle Posted June 5, 2017 Author Share Posted June 5, 2017 Thanks for the info, so I will pull the trigger on a new rear rotor. I didnt quite follow the last sentence can you clarify please. Link to comment
Michaelr11 Posted June 5, 2017 Share Posted June 5, 2017 I know that the min thickness of both the front and the rear rotors is 4.5mm,................ Also in respects to the rear rotor, does anyone have experience or advice regarding the cheap ones on ebay like this: A good quality replacement rear rotor on the R1100RT is the EBC MD653. I can't say how the Chinese eBay rotor compares to this, but the EBC rotor is much less than OEM and is good quality. Front replacements are MD607 (left-Side, Right-Side). Link to comment
McDuugle Posted June 6, 2017 Author Share Posted June 6, 2017 (edited) Will have a look at EBC as well, have heard a lot of good things about them. By any chance do you know the thickness of a new rotor out the box? Edited June 6, 2017 by McDuugle Link to comment
lkraus Posted June 6, 2017 Share Posted June 6, 2017 BMW repair DVD says a new rear disc is 5.0 mm, new front discs are "4.9...5.1 mm". I find the variation in front thickness a little weird. A result of different suppliers, or maybe model year changes? Wear limit is 4.5 mm rear, 4.6 mm front. Link to comment
Oldrider51 Posted June 6, 2017 Share Posted June 6, 2017 BMW repair DVD says a new rear disc is 5.0 mm, new front discs are "4.9...5.1 mm". I find the variation in front thickness a little weird. A result of different suppliers, or maybe model year changes? Wear limit is 4.5 mm rear, 4.6 mm front. Agree with rear rotor new thickness and wear thickness by my manual, front disc by my manual says front new thickness is 5.0 mm, wear thickness is same as indicated by Larry. Link to comment
AndyS Posted June 7, 2017 Share Posted June 7, 2017 BMW repair DVD says a new rear disc is 5.0 mm, new front discs are "4.9...5.1 mm". I find the variation in front thickness a little weird. Why Weird? If the item can live with wider manufacturing tolerance it will be cheaper for everyone. If you want an item such as a disc machined to tight tolerance they can, but will be reflected in price. It is after all, just a disc and it WILL change in size over its lifetime anyway. Link to comment
lkraus Posted June 7, 2017 Share Posted June 7, 2017 (edited) Weird because I've never seen such a large variation for a new disc. 0.2 mm difference is a lot. The skinny version would have 33% less usable material than a fat one. Edited June 7, 2017 by lkraus Link to comment
dirtrider Posted June 7, 2017 Share Posted June 7, 2017 BMW repair DVD says a new rear disc is 5.0 mm, new front discs are "4.9...5.1 mm". I find the variation in front thickness a little weird. Why Weird? If the item can live with wider manufacturing tolerance it will be cheaper for everyone. If you want an item such as a disc machined to tight tolerance they can, but will be reflected in price. It is after all, just a disc and it WILL change in size over its lifetime anyway. Morning__ My BMW 1100 dealer manual shows the same only in a slightly different way. 5mm nominal ± 0.1mm (0.1969" ± 0.003937") --Or just a little under .008" possible variation. (a standard 3x5 card usually runs about .008" thick. It's really not much of a problem as a little thicker (ie 5.1mm (.2008") is about a piece of printer paper thicker than nominal & the thinnest is 4.9mm (ie .192963") is only about a piece of printer paper thinner than nominal. This assumes they float to the extremes. In most cases they will probably mike closer to nominal. Link to comment
McDuugle Posted June 8, 2017 Author Share Posted June 8, 2017 Thanks for all the info all. All three of my rotors are close to min spec. I will give the $30 rear off ebay a shot. Does anyone know of any inexpensive replacements for the front, the floating rotors seam to be big bucks.... Link to comment
AndyS Posted June 8, 2017 Share Posted June 8, 2017 Thanks for all the info all. All three of my rotors are close to min spec. I will give the $30 rear off ebay a shot. Does anyone know of any inexpensive replacements for the front, the floating rotors seam to be big bucks.... The fronts should all be floating rotors, so factor in costs of bobbins, washers and E Clips. Link to comment
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now