New tyres feel funny

Hi all

Just had a couple of Insa Turbo Sahara's put on the back axle of my D2 after one of the Runway Enduro's got a puncture and ruined a sidewall. Since having them the car has felt a bit funny, as if the rear is snaking around (like when you go too fast towing a trailer) and it sometimes feels as if the car has a mind of its own. I've still got 2 road tyres on the front, so there's quite a difference in tread, although they are all 235/70 16's. Could this be caused by the difference in tread or is it just a MudTerrain thing? Is it just something that I'll need to get used to the feel of (obviously MT will be different to road tyres but wasn't expecting it to be this severe) or is there likely a bigger issue here?

If it's caused by the difference in tread presumably I'd be as well to replace the front two now also and be done with it for a while?

Matticus said:

Hi all

Just had a couple of Insa Turbo Sahara's put on the back axle of my D2 after one of the Runway Enduro's got a puncture and ruined a sidewall. Since having them the car has felt a bit funny, as if the rear is snaking around (like when you go too fast towing a trailer) and it sometimes feels as if the car has a mind of its own. I've still got 2 road tyres on the front, so there's quite a difference in tread, although they are all 235/70 16's. Could this be caused by the difference in tread or is it just a MudTerrain thing? Is it just something that I'll need to get used to the feel of (obviously MT will be different to road tyres but wasn't expecting it to be this severe) or is there likely a bigger issue here?

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Insas are fine on my 90, but I have them all round, and it doesn't go very fast. D2 is a much heavier, faster machine. What pressures are you running?

is there any way your springs have shifted when they jacked it up?

Pressures and speed may well be the issue here, they are not designed for speed, and they are sup[posed to be 80% off road

SmileySteve said:

Pressures and speed may well be the issue here, they are not designed for speed, and they are sup[posed to be 80% off road

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Would be my guess also, I don't think I would have those on a d2, would probably go with the Insa AT tyre, the Ranger.

I've got 38PSI in the insa's at the back, and around 34PSI on the front. The car starts to feel wobbly around 50MPH+. I don't really go above 65 usually but 60 is a challenge at the moment! Can't see that springs would've shifted given that they are airbag SLS springs on the rear.

In hindsight Turboman I do think the ranger's would've been a better option, although the Sahara's being 119.90 fully fitted for the pair seemed too good to miss for me. Now I'm unsure if I would've been better to spend the extra for some rangers

Matticus said:

I've got 38PSI in the insa's at the back, and around 34PSI on the front. The car starts to feel wobbly around 50MPH+. I don't really go above 65 usually but 60 is a challenge at the moment! Can't see that springs would've shifted given that they are airbag SLS springs on the rear.

In hindsight Turboman I do think the ranger's would've been a better option, although the Sahara's being 119.90 fully fitted for the pair seemed too good to miss for me. Now I'm unsure if I would've been better to spend the extra for some rangers

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Saharas are a good tyre,and excellent value but maybe not so well suited to that vehicle as Ranger.

I would try 40 psi in the backs, and 30 in the fronts, might take some of the flex out of the sidewalls on the MTs. I think those pressures are recommended for towing anyway.

Matticus said:

I've got 38PSI in the insa's at the back, and around 34PSI on the front. The car starts to feel wobbly around 50MPH+. I don't really go above 65 usually but 60 is a challenge at the moment! Can't see that springs would've shifted given that they are airbag SLS springs on the rear.

In hindsight Turboman I do think the ranger's would've been a better option, although the Sahara's being 119.90 fully fitted for the pair seemed too good to miss for me. Now I'm unsure if I would've been better to spend the extra for some rangers

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what is the listed in the box on side of the tyre. Low psi will give sidewall flex and very poor handling at speed. Are they retreads/recaps or new tyres

Thor1950 said:

what is the listed in the box on side of the tyre. Low psi will give sidewall flex and very poor handling at speed. Are they retreads/recaps or new tyres

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Possibly only a max. pressure. The lr owners handbook gives pressure options for different loading and uses.

Haven't looked on the side of the tyre but I tend to ignore this, because as turboman says they tend to be a max pressure only and far too much for day to day use.

Would there be any logic in getting the tyres swapped from the disco 2 to my disco 1, putting the grabber UHP's from the D1 onto the D2, as the D1 is lighter I believe, and doesn't go very fast anyway?

They are remoulded tyres AFAIK

Turboman said:

Possibly only a max. pressure. The lr owners handbook gives pressure options for different loading and uses.

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Yes I understand that. But those tyres are not original. Bet they are a higher rating than factory spec tyres. They are probably a LT (light truck) tyre with a heavier side wall and tread construction. where original is probably a P rated (passenger car tyre) If a heavier rated tyres was installed the the recommended PSI does not apply. My truck came from factory with a D load rating which has a lower PSI recommendation. When I replaced them I went to a load range E rating (higher load carrying ) and required 10PSI more than factory recommended for a lower rated tyre

Thor1950 said:

Yes I understand that. But those tyres are not original. Bet they are a higher rating than factory spec tyres. They are probably a LT (light truck) tyre with a heavier side wall and tread construction. where original is probably a P rated (passenger car tyre) If a heavier rated tyres was installed the the recommended PSI does not apply. My truck came from factory with a D load rating which has a lower PSI recommendation. When I replaced them I went to a load range E rating (higher load carrying ) and required 10PSI more than factory recommended for a lower rated tyre

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Probably much lower rated than standard. Insas are cheap remoulds, D2s probably came with expensive premium brand tyres as new.

When I first read OPs post, I was actually very surprised that Insas are high enough speed rating for D2.

Turboman said:

Probably much lower rated than standard. Insas are cheap remoulds, D2s probably came with expensive premium brand tyres as new.

When I first read OPs post, I was actually very surprised that Insas are high enough speed rating for D2.

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That will explain the problem. Buy cheap get cheap, Brit part anyone

Thor1950 said:

That will explain the problem. Buy cheap get cheap, Brit part anyone

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Great skins on a 90 or a series, which don't go very fast on the road. Just not so sure if they are good on D2.

The Sahara's are 105 Load rating, speed rating Q (95MPH), rangers 106 Load, speed S (106mph) from what i can find 105 is standard load rating with speed rating of H (133mph) but this is unnecessary surely?!

Matticus said:

The Sahara's are 105 Load rating, speed rating Q (95MPH), rangers 106 Load, speed S (106mph) from what i can find 105 is standard load rating with speed rating of H (133mph) but this is unnecessary surely?!

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Probably unnecessary in purely practical terms, but I think it is a legal requirement to use same speed rating as original fitment. I am not sure, but a tyre fitter should advise.

Fitment may be same over whole d2 range, which would include the V8s. They are quite fast, probably not 130 mph, but I would think over 106 mph.

The V8 top speed is 105 mph claimed, and the TD5 is 97mph. It's fine to reduce the speed rating down as far as the manufacturers claimed top speed, so yes I suppose 105mph could be argued but the TD5 has separate figures published so can't imagine it'd matter... That being said 95mph is still not quite enough!

The 300tdi however had a top speed of 90mph so perhaps I would be better to swap these Sahara's over to the 300tdi.

In an attempt to keep on topic though, is there anything I can do, be it on the TD5 or the 300tdi to try and keep the car at least a little bit more stable? pump up the tyres a bit higher best option?

my D1 200tdi is set at 28psi front 34psi rear on standard 235/70r16 road tyres if thats any help and it's perfectly stable up to 90mph 26psi front is the recommended but I find it's a little squirmy at that but then I'm quite specific with my tyre pressures so trying a lower front to rear pressure could help

personally id get them off asap being as you only fitted 2 wonder you aint crashed it ,afterall they are cheap retreads designed for mostly offroad/laning.imo fit 4 of the same brand/make always, don't mix/match

wil2813 said:

personally id get them off asap being as you only fitted 2 wonder you aint crashed it ,afterall they are cheap retreads designed for mostly offroad/laning.imo fit 4 of the same brand/make always, don't mix/match

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+1 you said that they don't feel safe
As you have the option to swop them with your other motor,you should

changing the pressure a couple of PSi will not make them a road Tyre :bump2: