16" v 18" wheels - sidewall height and ride quality

**bidds** · 27th September 2013, 08:12 PM

My D2a has the 18" wheels, ACE and standard size tyres. It has new'ish genuine shocks and everything is in good repair: the ride isn't exactly plush but I'm happy considering the handling. However, I'm thinking about slightly higher sidewalls to give a plusher ride on horrible corrugations and have the following question:

How much more sidewall do I need to make a useful difference?

I could go to 255/60R18 and that'll give an extra 1/2" sidewall height and allow the spare to stay on the existing mount.

I've driven an ACE equipped D2 with the std 235/70R16 and thought the ride/handling compromise was excellent. That's an extra 1" sidewall height.

Would the 255/60R18 provide much of an improvement? This would be my preferred option if there was an improvement: I like the 18" wheels and it'll be much cheaper. I could fit Grabber AT2 - same as I have now; quite a good tyre.

I could also go to 16's fitted with 255/70R16 for the same outer diameter as the 255/60R18 and get an extra 1.5" sidewall height. That has the attraction of being able to fit LT tyres - I'd probably go for BFG ATs.

Grateful for any experience on this one.

cheers, bidds

**Pedro_The_Swift** · 28th September 2013, 07:30 AM

My green one on 16's definitely rode better.

**PhilipA** · 28th September 2013, 08:15 AM

I just did exactly what you say with my new/old D2.

The 16 inch wheels with 255 70 16 BFG AT KO give a much less "jittery" ride than the 255 55 18 cheapo Chinese . The main difference is in crashing into sharp bumps on bitumin.

The 255 70 16 BFGs seem to give a rougher ride than previous BFG 245 75 16 that I had on my RRC but in fact the whole D2 gives a rougher ride IMHO, probably because the rear springs are harder. It seems to smooth a lot even with a small load on eg wife and grandchildren.

BTW you can fit 245 75 16 BFG if you can find 7 inch rims from early D2. I have 8 inch 38A rims so was forced to get the 255s.

I think the reason is that they are 116 load rating vs 112 or whatever for the others.
Regard sPhilip A

Tombie · 28th September 2013, 09:54 AM

Whilst not getting into the legality, 265-60-18LTs will fit..

**Designosaur** · 29th September 2013, 07:02 PM

I went with the 255/60-18 on mine, Pirelli ATR's, they look great.

_DSC7683.jpg by berniecram, on Flickr

I can't compare to 16's though but they handle really well on dirt roads, which is where I will be giving it a lot of use.

Bernie

**PhilipA** · 29th September 2013, 08:31 PM

Even with 255 60 18 , you are still an inch down on sidewall vs a 255 70 16

While it doesn't sound much it is about 16% and about 2 inches or 30% or so on a 255 55 18...

Are your tyres LTs and what is the load rating?

I prefer LTs due to their potentially greater durability, although they probably give a rougher ride than passenger tyres.

I have gone to a lot of trouble and expense so I hope my efforts are rewarded. I plan a 3 month trip next year to the Kimberley etc so unless the useage is going to be on rough rocky dirt roads it could be considered overkill.
Regards Philip A

**99TD5** · 30th September 2013, 10:16 AM

I went from 18's to 245/70/16 and the comfort factor is very noticeable.

Whilst I enjoyed the handling with ACE & 255/55/18 it was a harsher ride, SWMBO is much happier with the ride now which makes for a much better driving experience for me

**gusthedog** · 30th September 2013, 11:45 AM

Originally Posted by 99TD5

I went from 18's to 245/70/16 and the comfort factor is very noticeable.

Whilst I enjoyed the handling with ACE & 255/55/18 it was a harsher ride, SWMBO is much happier with the ride now which makes for a much better driving experience for me

I have the same as 99 TD5 (245/70 16) in a BF Goodrich All Terrain in LT. I Find the ride and handling great. I came down from 235/85 16s as SWMBO is short and the TD5 was way down on power in the hills with the bigger size. EGTs went up a heap with the engine doing more work on the larger tyres. As we live surrounded by hills, the 245/70 is perfect for us

Also, the bigger tyres moved around a heap more due to sidewall flex making the ride pretty crappy.

Tombie · 30th September 2013, 02:21 PM

265-70-18s give a great ride

Don't forget your pressures play a huge part I. Ride comfort. Offroad dropping pressures will have a significant improvement in ride quality.

**bidds** · 1st October 2013, 08:44 PM

Thanks for your experience and thoughts - very useful and helps reaffirm the value in moving to 255/70R16. Sorry Tombie - I'm going to keep it legal, nothing huge for this black duck - too lazy to make them fit. Good point about pressure and ride comfort: I already drop pressures off road so I guess the primary driver to the move to 16's is on-road comfort.

Supplementary question, if I may: Has anyone found any shock that provides a decent ride with 18's?

I've put bilsteins on before but hated them (as I did on my Rangie - can't say I've not persisted); I'm now running the correct LR brand shocks for a D2a and had figured they'd be as comfortable as it gets. However, it's just occurred to me that there's a single shock for the D2a (not every permutation of SLS/Coil and ACE/no-ACE as for the earlier D2) - and I'd have to assume it's not valved specifically for the 18" wheels.

I'm going to go to Koni Heavy Track Raid shocks all round. My thinking is that doing them before changing tyres keeps the slim chance that good shocks can make a difference.

Thanks again

Thread: 16" v 18" wheels - sidewall height and ride quality

Thread Tools

16" v 18" wheels - sidewall height and ride quality

Bookmarks

Bookmarks

Posting Permissions