ABS warning light from reduced tyre diameter?

[genphreak]

True or False?

The dude at my local tyre shop told me that dropping my tyres from 55 to 50 profile would run the risk of an ABS warning on the dash.

I did it anyway as I am sure my old tyres (225/55x16) are a little larger than the factory 225x15x60s.

I have dropped them so my snow chains will fit easier and I will get slightly better economy. Primarily I want to go harder round corners with the fat sways/lowered springs Kristian helped me fit last year this should be good.

Maybe I'm just nuts? My 225/50 seems tall enough... but the ride on Bilstein Sports on the way home this afternoon is ever so slightly sharper, though this outcome is a little less noticable than the handling improvement- it is woohoo hang on tight around the benzzz! Nick

I got 225/60/ZR16 Dunlop SP2000Es. They are made in Germany (ya! das gut!) but cost more than the better model (SP3000A) that is Made in Australia. (I had one anyway and wanted to get a match for it), but knowing the gurus that big companies hire to do their marketing the German one is better than the model up... Anyway I don't want directionals as the rims are directional which makes for too complicated a rotation procedure, so there isn't much choice. Apart from Pilot Sports and Conti Sport Contacts (M5 tyres!), the SP2000Es aren't a bad deal. Otherwise I would have stuck on the Conti Premier Contacts and been done with it...

Maybe I should have. Bah, I dunno oh well- how will life be on 50 series tyres I wonder... and will I get the ABS warning the dude thought I would get?

[Zeuk in Oz]

True or False?

The dude at my local tyre shop told me that dropping my tyres from 55 to 50 profile would run the risk of an ABS warning on the dash.

I did it anyway as I am sure my old tyres (225/55x16) are a little larger than the factory 225x15x60s.

I have dropped them so my snow chains will fit easier and I will get slightly better economy. Primarily I want to go harder round corners with the fat sways/lowered springs Kristian helped me fit last year this should be good.

Maybe I'm just nuts? My 225/50 seems tall enough... but the ride on Bilstein Sports on the way home this afternoon is ever so slightly sharper, though this outcome is a little less noticable than the handling improvement- it is woohoo hang on tight around the benzzz! Nick

I got 225/60/ZR16 Dunlop SP2000Es. They are made in Germany (ya! das gut!) but cost more than the better model (SP3000A) that is Made in Australia. (I had one anyway and wanted to get a match for it), but knowing the gurus that big companies hire to do their marketing the German one is better than the model up... Anyway I don't want directionals as the rims are directional which makes for too complicated a rotation procedure, so there isn't much choice. Apart from Pilot Sports and Conti Sport Contacts (M5 tyres!), the SP2000Es aren't a bad deal. Otherwise I would have stuck on the Conti Premier Contacts and been done with it...

Maybe I should have. Bah, I dunno oh well- how will life be on 50 series tyres I wonder... and will I get the ABS warning the dude thought I would get?

It will be interesting to see what you think of the Dunlops, Nick.

Did he give a reason as to why you would get the ABS light on ? I can't think of one.

[BigKriss]

I doubt it either. I've been running 225/50/15 from the usuall 225/60/15 for over a year now on the front with no worries.

[winfred]

as long as you have the same size all the way around the abs system doesn't care, it looks for a difference in wheel speed from one wheel to another overall speed is not a factor

[Barry]

On holiday,destroy 2 tyres on the e39 528i..
I could only get 225/50/16.Fitted them to the front...
Id do maybe 5 km and the ABS would come on..and stay on.
Differential reading front back.

[winfred]

the system detects a hard fault and turns itself off, it thinks it has some bad sensors in this situation

On holiday,destroy 2 tyres on the e39 528i..
I could only get 225/50/16.Fitted them to the front...
Id do maybe 5 km and the ABS would come on..and stay on.
Differential reading front back.

[genphreak]

the system detects a hard fault and turns itself off, it thinks it has some bad sensors in this situation

Thanks guys.

Farout. I intended to get the same for the rear... but until I do that the ABS will probably trigger. Great. At least it made it through rego before any warning.

Hmm should have stuck with 55s. Well, I hope the ride isn't a major problem, there is fair difference in profile of 11.25mm from what I had prior.

ie using Anthus Engineering's wheel geometry calculator these are the differences;

225x60x15 Dia: (25.63") * Factory
225x55x16 Dia: (25.74") Speedo change +0.4%
225x50x16 Dia: (24.86") Speedo change -3.0%

Hopefully 3% won't trigger the light... However I imagine if it could upset ABS operation in an emergency stop... I might have to swap the other 55 series (new) tyres real quick... ouch- that'd be expensive

If the warning light comes up I'll post.