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Oversized wheels
Posted: Sun Mar 16, 2014 10:48 pm
by abernethybongo
Hi folks,
Having read Torchwood's guide to getting better mpg, I'm interested in fitting larger wheels to our Bongo, but I've got a few questions which I wondered if anyone might be able to enlighten me on?
- Our Bongo is 4WD, so we'd need to fit larger wheels all round - has anyone fitted 16 or 17" tyres at the front - do they bind on the arches at full lock?
- Does it become a nightmare to get insurance? A recent check on comparethemeerkat doubled our quotes if certain modifications had been made.
- In my mind (dredging out the high-school physics), bigger wheels could mean poorer braking (increased radius giving greater leverage/force acting against the brakes) - I'd be happy to be corrected, has anyone experienced worse braking performance on bigger wheels?
Many thanks,
Jamie
Re: Oversized wheels
Posted: Sun Mar 16, 2014 11:20 pm
by The Great Pretender
Hi, I also fitted larger wheels a few years ago after reading Torchwoods post. It isn’t the larger wheels that can cause a problem it is the aspect ratio of the tyres.
I fitted 225/55/17 to my 2 wheel drive Bongo, if I remember correctly it raises the overall gearing by about 5% with no fouling problems and as a added bonus the speedo reads virtually correct. There is no noticeable difference when driving, accelerating or braking................
Re: Oversized wheels
Posted: Mon Mar 17, 2014 8:00 pm
by Simon Jones
Larger circumference wheels could result in the speedo under reading which would be illegal and you would need to remember to drive under the indicated speed to reduce risk of getting speeding ticket.
Re: Oversized wheels
Posted: Mon Mar 17, 2014 8:05 pm
by mikeonb4c
The Great Pretender wrote:Hi, I also fitted larger wheels a few years ago after reading Torchwoods post. It isn’t the larger wheels that can cause a problem it is the aspect ratio of the tyres.
I fitted 225/55/17 to my 2 wheel drive Bongo, if I remember correctly it raises the overall gearing by about 5% with no fouling problems and as a added bonus the speedo reads virtually correct. There is no noticeable difference when driving, accelerating or braking................
Ditto. Yours should be fine as long as same size fitted all round

Re: Oversized wheels
Posted: Tue Mar 18, 2014 7:34 am
by mikexgough
Running 17's and using 215/65/15 as the reference (rear tyres) then .........225/50/17 Tyres are pretty much spot on where at 30 mph ...you will be doing 29.8 mph and at 60 mph 59.7 mph... obviously speedo's can be "out" slightly.
225/55/17 Tyres are 2.8% larger and at 30 mph you will be at 30.9 mph & at 60 mph it's 61.7 mph....
You can get 225/50's rated at 98 which is above the Bongo's 96 and the 225/55's rated at 101.... yer pays yer money and all takes your choice... I have used both sizes...
Tyre Calculator
Re: Oversized wheels
Posted: Tue Mar 18, 2014 9:43 am
by mikeonb4c
My sat nav had the 55s as being spot on true speed but more importantly, they were noticeably nicer to ride on than the harsh 50s (with cracked inner walls!) they replaced. Yer pays yer money etc.

Re: Oversized wheels
Posted: Tue Mar 18, 2014 11:23 am
by mikexgough
never really noticed the ride difference personally.... mileage wise was similar as was tyre life.... and the speedo ...I found the 225/50's more accurate on mine.... Yer Pays Yer Money and all that ....
one thing I would say.... keep away from Directional tyres and go for Asymmetric pattern as I was advised by my Tyre fitter... they are much quieter...the set of Directional I had droned and droned.... Asymmetrics are quiet... Some may have different experiences with Directionals and I'd like to hear if anyone had
Re: Oversized wheels
Posted: Tue Mar 18, 2014 12:40 pm
by Spencer54
I have 18" 225 40 18 XL on RX8 wheels - cost £25 more for insurance.
That was it, looks better, handles better - but harder ride.
They are exactly the same rolling diameter as the 15", no issues whatsoever.
Complete cost was £155 that includes wheels, delivery and insurance.
Re: Oversized wheels
Posted: Tue Mar 18, 2014 6:14 pm
by mikeonb4c
mikexgough wrote:never really noticed the ride difference personally.... mileage wise was similar as was tyre life.... and the speedo ...I found the 225/50's more accurate on mine.... Yer Pays Yer Money and all that ....
one thing I would say.... keep away from Directional tyres and go for Asymmetric pattern as I was advised by my Tyre fitter... they are much quieter...the set of Directional I had droned and droned.... Asymmetrics are quiet... Some may have different experiences with Directionals and I'd like to hear if anyone had
Might have been because the 55s were a superb new set of Pirelli P7s that I got off eBay for £180. I was floating on a cloud after that.

Re: Oversized wheels
Posted: Tue Mar 18, 2014 10:06 pm
by mikexgough
Spencer54 wrote:I have 18" 225 40 18 XL on RX8 wheels - cost £25 more for insurance.
That was it, looks better, handles better - but harder ride.
They are exactly the same rolling diameter as the 15", no issues whatsoever.
Complete cost was £155 that includes wheels, delivery and insurance.
Can I ask what the load rating of those tyres are?.... as most that size are 92 load rating...even though they are XL...
I know most Bongo owners with 18's go for 235/45/18 as they are 98 load rating
I only ask as Bongo's are 96 rated and I don't want you to fall foul of your Insurance company ....
Re: Oversized wheels
Posted: Tue Mar 18, 2014 11:33 pm
by The Great Pretender
Another plus point of 225 55 17 tyres is that they keep the rim above most kerbs.
Re: Oversized wheels
Posted: Wed Mar 19, 2014 6:45 am
by mikeonb4c
The Great Pretender wrote:Another plus point of 225 55 17 tyres is that they keep the rim above most kerbs.
Again, that was my finding too.
Re: Oversized wheels
Posted: Wed Mar 19, 2014 10:51 am
by mikexgough
and a lot of 225/50's have rim protectors on the sidewalls...
A lot to consider....
Re: Oversized wheels
Posted: Sat Mar 22, 2014 1:11 pm
by abernethybongo
Thanks guys - a lot to consider as you say! I'll give it some thought....
Cheers,
Jamie
Re: Oversized wheels
Posted: Tue May 20, 2014 5:25 pm
by schmoo_smith
abernethybongo wrote:Hi folks,
Having read Torchwood's guide to getting better mpg, I'm interested in fitting larger wheels to our Bongo, but I've got a few questions which I wondered if anyone might be able to enlighten me on?
What's the link to this guide?