Please Help. ABS issues.

[Smathersfish]

Thanks in advance for any help.

I just got a 2014 R3R ABS. Just put new tires on and am now having a rear ABS problem. I put on a Bridgestone EMax 240/55 and Michelin Commander 2 140/75 to try to quicken the steering a little. The bike handles much better!

The problem is that the rear brake ABS is being activated to such an extent that I really dont have rear brakes! The rear brake works a little at slow speeds but gets less effective as speed increases. Above 60 or 70 MPH you cant even depress the brake lever!

I have read some threads on here about changing tire sizes and changing to this combination seems to have a lot of support. My ABS light is not on. I'm thinking that going bigger on the back AND smaller on the front is causing my issues. What do y'all think?

 

[1olbull]

Thanks in advance for any help.

I just got a 2014 R3R ABS. Just put new tires on and am now having a rear ABS problem. I put on a Bridgestone EMax 240/55 and Michelin Commander 2 140/75 to try to quicken the steering a little. The bike handles much better!

The problem is that the rear brake ABS is being activated to such an extent that I really dont have rear brakes! The rear brake works a little at slow speeds but gets less effective as speed increases. Above 60 or 70 MPH you cant even depress the brake lever!

I have read some threads on here about changing tire sizes and changing to this combination seems to have a lot of support. My ABS light is not on. I'm thinking that going bigger on the back AND smaller on the front is causing my issues. What do y'all think?

WOW!
Finally someone with the same weird issues as I!!! Only with the rear ABS.
Tis not your tires as the circumference ratio is well below the ECM tolerance.

Since I frequently hoon, I have reckoned over heating and went with ceramic pads - helped but did not completely eliminate . . .
I bought the "Dealer Tool" and bled the $hit outta them to no avail . . .
I have also fully drained the master cylinder, refilled and bled = NG . . .
For me. the issue comes and goes, but has caused me to reduce my hoon speeds to accommodate a possible braking delay.

I recently got a reverse bleeder. It worked well on my front brake lines replacement, so we shall see . . .

 

[warp9.9]

Check the run out on the ABS ring. I dont have abs but remember it seems to be easy to knock it off kilter and set the lihht off.

 

[Smathersfish]

Check the run out on the ABS ring. I dont have abs but remember it seems to be easy to knock it off kilter and set the lihht off.

That and making sure the sensor was clean were the first things I did. Thanks

Can I totally disable the ABS?

 

[1olbull]

Put a 130 front tire on it that will do it!
Actually a good question. I look forward to reading a serious answer.

 

[barbagris]

Finally someone with the same weird issues as I!!! Only with the rear ABS.
Tis not your tires as the circumference ratio is well below the ECM tolerance.

Unless of course there is tolerance in that ECM tolerance value.

 

[Ishrub]

Unless of course there is tolerance in that ECM tolerance value.

That was my thought too, as 130 profile were known to cause a problem 140 may be on the edge for some, particularly in certain road conditions where the potential for mis-matching of the front and rear rotational speeds could be linked to more slippery or grippy road conditons than usually encountered. Note the very high traction of typical NZ and Australian road surfaces with crushed rock and tar construction common compared to super smooth slick concrete or non-aggressive tarmac more typical elsewhere.

Edit:
'or grippy' - as less surface slip would allow the effect of the circumferential difference to be greater.

 

[barbagris]

I know this has been chewed over before. I remember @1olbull put some effort into it.

BUT....... have we aver ACTUALLY discovered the Official Tolerance Values?. I confess I have never worried too much as I have a pre-ABS bike.

Because EU regs allow a +/- 3% per tyre - I think we're safe assuming a 6% total difference as minimum value.

But (on paper) - rather than actual MEASURED an E-Max is 3.7% over and a 140/75 is 4.5% under - that's 8.3%.

The truth is thought that not all 140/75 are going to be identical in rotational circumference - and wear rates front vs rear will also play their part. Though from experience not all mfrs publish them.

Also tread depth may play a role. So (speculating) the 140/75 is the (paper) carcass size - so 5mm tread depth or 7mm tread depth new will affect this circumference too.

My gut says that the rear is set to fail as a mismatch warning rather than the front.

 

[R-III-R Turbo]

Can I totally disable the ABS?

i'm no ABS expert but sounds like your rear tyre diameter increase and front tyre diameter decrease has resulted in the ABS unit seeing slower rotational speed on the rear due to the larger circumference of it, ratio-wise, vs the front tyre circumference.
and it sees the slower rotation of the rear as a partial lock-up of the rear, and reacts

re disabling the ABS, not sure it's wise, but i do know if you disconnect the ABS unit you won't get a fault code on your clocks - don't know if it will leave your brakes working ok though

you can disconnect it by removing the exhaust crossover, popping off the ABS box cover, 3 bolts iirc, off the side of the black box on the right side between engine and rear wheel. the harness connects in with an orange/black plug, you slide the orange bit up, and the plug just slides off

 

[Jag]

Could you disconnect the sensor wires from the rear brake and see what happens? Or remove the fuse for the abs? Just thinking out loud. Purely for testing/diagnosic only?