Does it make any difference at all if you have 17" or 18" wheels fitted to your car when towing ???. It may sound a simple question, but I don't know the answer. I asked the wife and she just smiled.
Frank
Frank
does it matter 17" 18"
- Thread starter Val & Frank
- Start date
14" and 15" are the norm for caravan tyres. I think you'd be pushed to find ultra-low profile tyres with adequate load carrying capacity that you would need if you had 17" or 18" wheels fitted.
Hi Frank,
Agree with Lutz, especially when you consider that a proprotion of the caravan suspension is made up of sidewall flexure in an 80 aspect ratio tyre.
Change the 80 to a 45 section low profile tyre and most of the flexure will have gone - so if you go the low profile route, then the next time you tow get ready to pick all the crockery off the floor.
Robert
Agree with Lutz, especially when you consider that a proprotion of the caravan suspension is made up of sidewall flexure in an 80 aspect ratio tyre.
Change the 80 to a 45 section low profile tyre and most of the flexure will have gone - so if you go the low profile route, then the next time you tow get ready to pick all the crockery off the floor.
Robert
Hi Frank
I had 18 inch low profiles on my previous car (Mondeo) and it towed like a dream. Cornering was superb solo.
Lisa.
I had 18 inch low profiles on my previous car (Mondeo) and it towed like a dream. Cornering was superb solo.
Lisa.
Thanks Graeme I was requesting information on the car. I thought it may make some difference to how the pressure is exerted onto the back of the car.
Thanks
frank
Sorry, misread the original question. Yes, low profile tyres should improve towing stability because the have less lateral compliance.
Frank, don't think it should make too much difference to loads on the back of the car providing you stick to the correct max towbar weight (probably about 75kg). I think the only thing you will notice is a bumpy ride because of the low profile tyres on bigger wheels. hth.
Frank,
Oh crud. I read the response from Lutz and misread your posting. Sorry.
But I'll still agree with Lutz, and if you already have the car and change your wheels remember to inform your insurer - it's a modification to type approved equipment.
If you are buying a new car - check that if the lower profile tyres come with lowered suspension that the car is still homologated to have a tow hook.
Robert
Oh crud. I read the response from Lutz and misread your posting. Sorry.
But I'll still agree with Lutz, and if you already have the car and change your wheels remember to inform your insurer - it's a modification to type approved equipment.
If you are buying a new car - check that if the lower profile tyres come with lowered suspension that the car is still homologated to have a tow hook.
Robert
Frank doesn't matter just make sure that your tyre pressures are correct for the wheel size as per the car manual (should be higher for 18" than 17")
Hi Frank.
Now while the 18 inch rims fitted with lower profile tyres would give better results on tarmac with their stiffer latteral support from the lower profile tyre. On grass things would be very different. There you gain better grip with a higher profile tyre and low air pressure.
If the car is normally fitted with 18 inch tyres and you go down a size in diameter to 17 inch, first of all you will get a discrepencey in the speedo reading as at 30mph on the speedo the car could be doing about 27mph. But you will get a better pulling affect up hills due to effectively lowering the gear ratios.
Going from 17 inch to 18 inch rims has the opposite affect and you could end up getting a ticket for speeding. You would also notice lower pulling power.
The main criteria in changing rim sizes is that you normally adjust the profile type (55/60/65/70) so that you don't actually alter the rolling diameter of the wheel, which then has a neutral affect on gearing.
I run 65 series tyres on my Laguna (1998)while towing our twin axle van and find that the road holding is good. If I get stuck on grass, all I do is drop the tyre pressure to about 10 Psi in the front tyres which has the affect of putting a larger foot print of tyre on the ground and giving elasticity in the tyre. With this done I've not yet been unable to tow the van off most fields. Then with my trusty 12 volt air pump I reinstate the 30Psi needed for use on the roads.
So there's a tip to try next time you get stuck on the field.
One other thing about getting stuck is, don't let your wheels spin as the tyres become clogged with soil and effectively you have then got racing slicks. Dropping the tyre pressure first helps on wet grass, but only if the tyre treads are relatively mud free.
Give it a try next time, you'll be suprised at the result.
Steve.
Now while the 18 inch rims fitted with lower profile tyres would give better results on tarmac with their stiffer latteral support from the lower profile tyre. On grass things would be very different. There you gain better grip with a higher profile tyre and low air pressure.
If the car is normally fitted with 18 inch tyres and you go down a size in diameter to 17 inch, first of all you will get a discrepencey in the speedo reading as at 30mph on the speedo the car could be doing about 27mph. But you will get a better pulling affect up hills due to effectively lowering the gear ratios.
Going from 17 inch to 18 inch rims has the opposite affect and you could end up getting a ticket for speeding. You would also notice lower pulling power.
The main criteria in changing rim sizes is that you normally adjust the profile type (55/60/65/70) so that you don't actually alter the rolling diameter of the wheel, which then has a neutral affect on gearing.
I run 65 series tyres on my Laguna (1998)while towing our twin axle van and find that the road holding is good. If I get stuck on grass, all I do is drop the tyre pressure to about 10 Psi in the front tyres which has the affect of putting a larger foot print of tyre on the ground and giving elasticity in the tyre. With this done I've not yet been unable to tow the van off most fields. Then with my trusty 12 volt air pump I reinstate the 30Psi needed for use on the roads.
So there's a tip to try next time you get stuck on the field.
One other thing about getting stuck is, don't let your wheels spin as the tyres become clogged with soil and effectively you have then got racing slicks. Dropping the tyre pressure first helps on wet grass, but only if the tyre treads are relatively mud free.
Give it a try next time, you'll be suprised at the result.
Steve.
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