Great start to 2015......... NOT!

[Syndrome]

The first rays of light for 2015 had not yet appeared and I copped a puncture on the way home.

It was only approximately a 4km trip. Started on a gravel road, then when I got on tar I hear a 'tick tick tick' noise from the right rear. Thinking it was a stone stuck in the thread I kept driving with the thought it would eventually dislodge itself. Most of the trip was in 60 and 50 km/hr zones with one short stretch in an 80 zone.

Was about 500 metres from home when the back end of the car started vibrating. Back off and crawled it into the driveway. Yup, flat tyre. Have since removed the flat (which has a nice screw in it) and put on the space saver spare. First drive after putting on the spare and get warning messages about ABS and DSC not working. WTF!?!?!? Just because of a flat tyre? Did the vibration dislodge something? I have no idea.

[calais]

If the spare is a different size (rolling diameter) the abs and dsc wont work.

[Franco Cozzo]

Originally Posted by calais

If the spare is a different size (rolling diameter) the abs and dsc wont work.

Yep, wheel speed sensor would be picking up different speed on one wheel to the other and it would throw a code.

I'm pretty sure space savers are supposed to be the same or close to rolling diameter as the wheels they're designed to replace as a spare though, correct?

[Syndrome]

I am using the space saver which was supplied with the car when purchased brand new. You would think the Ford engineers specified a spare tyre which would be compatible.

BTW - the codes are logged as soon as I turn on the car. The wheels have not yet moved so it could not be due to different rolling diameters.

[Franco Cozzo]

Check wheel speed sensor wires/connector for damage, I snapped mine off on a speed hump after the car was lowered.

[csv8]

The space saver in my Fiesta is 1" smaller than normal tyres on the car. Don't know how that works ???
But my i20 has a full size spare...no space saver or can of goo!!!

[Franco Cozzo]

Originally Posted by csv8

The space saver in my Fiesta is 1" smaller than normal tyres on the car. Don't know how that works ???
But my i20 has a full size spare...no space saver or can of goo!!!

My Focus has a space saver spare, but I've got a full sized spare in the boot now too.

[BIONIC MAN]

No, It would have picked the difference in rolling diameter of the previously flat tire...
You just didn't notice with all the other vibrations and trying to get to your driveway?!

[Elks]

Originally Posted by BIONIC MAN

No, It would have picked the difference in rolling diameter of the previously flat tire...
You just didn't notice with all the other vibrations and trying to get to your driveway?!

This.....

Take it for a short run with the space saver on. It may correct itself.

[vztrt]

Originally Posted by Syndrome

I am using the space saver which was supplied with the car when purchased brand new. You would think the Ford engineers specified a spare tyre which would be compatible.

BTW - the codes are logged as soon as I turn on the car. The wheels have not yet moved so it could not be due to different rolling diameters.

Ran the cheese cutter on the old SR for a week (had tyres booked in and then it let go on the monday) and never had this drama. 17 inch and it never did this. You sure the wheel speed sensor hasn't been damaged?

[XR Martin]

We had a Kia Cerato that the DSC light was coming on due to the back tyres being about 80% worn and new tyres on the front.

[Syndrome]

Originally Posted by BIONIC MAN

No, It would have picked the difference in rolling diameter of the previously flat tire...
You just didn't notice with all the other vibrations and trying to get to your driveway?!

I hope you are correct.

[kypez]

Is your space saver at the right pressure? They need to be at 60PSI.

My car threw up a ABS/DSC/Check Engine error for having the rears at 50PSI instead of 41 as per recommended.

[Syndrome]

Originally Posted by kypez

Is your space saver at the right pressure? They need to be at 60PSI.

My car threw up a ABS/DSC/Check Engine error for having the rears at 50PSI instead of 41 as per recommended.

I saw it says on the space saver to inflate it to 60psi but that seems absurdly high.

[kypez]

Originally Posted by Syndrome

I saw it says on the space saver to inflate it to 60psi but that seems absurdly high.

Not really as it's a lot smaller.

PSI is pounds per square inch. Reduce the area, you need to increase the pressure. Same reason a bicycle tyre is inflated to 110 PSI cause it's area is so small.

Set the right pressure and the light show should end.

[BIONIC MAN]

Come on syndrome... Was I right?
I can't sleep at night not knowing what made your abs light come on

[Syndrome]

Originally Posted by BIONIC MAN

Come on syndrome... Was I right?
I can't sleep at night not knowing what made your abs light come on

Still TBA. Will keep you posted.

[mcnews]

Driving on a flat tyre can also ruin wheel bearings and also ruin your shock absorber on that side.

[Syndrome]

Originally Posted by BIONIC MAN

Come on syndrome... Was I right?
I can't sleep at night not knowing what made your abs light come on

Interesting. Put the patched tyre back on the car yesterday. Keyed-on and no warning lights or buzzers before the wheels had even moved and no further warning lights or buzzers after I started to drive the car. I was of the understanding that the system did a self-check once one started driving the car, not while it was stationary.

[Iggle Piggle]

I'm thinking if putting the 'proper' wheel back on cleared it then your car was probably just throwing a "get this pox looking wheel off me" code.

[superpursuit83]

How would different wheel diameter mess with abs/speed sensor? They read off the tone wheel,not the outside of wheel

[351@GT]

Originally Posted by superpursuit83

How would different wheel diameter mess with abs/speed sensor? They read off the tone wheel,not the outside of wheel

smaller circumference of the wheel means to travel the same distance it will turn more times, hence different wheel speed.

[kypez]

Did you set the pressure of the spare to 60 PSI?

[Syndrome]

Originally Posted by 351@GT

smaller circumference of the wheel means to travel the same distance it will turn more times, hence different wheel speed.

As I said in my previous posts, the warnings started before the wheel have even started to turn and cleared before the wheel started to turn.

[351@GT]

Originally Posted by Syndrome

As I said in my previous posts, the warnings started before the wheel have even started to turn and cleared before the wheel started to turn.

Yes, you would think it would only reset after the car moved. Maybe those particular warnings clear after a time period of the car not in use.

My post was only explaining how/why the car would detect different wheel speeds.