Different tyres on back axle - how bad is this?

MichaelR

Hello,

I have a Kia Picanto. I noticed the two front tyres were nearly down to the legal limit, ordered brand tyres for them for max safety (Uniroyal Rainexpert) from a tyre garage and when the tyres arrived there, I went to get them fitted.

Fit they did, but on inspection, ONE of the rear tyres was nearly down to the legal limit too. The other has quite a lot on it yet, so apparently they already were different. (My guess is, when I was buying it a bit over a year ago, the dealer replaced one rear tyre).

They had a budget tyre of that size available (Hifly) so I got the one bad rear tyre replaced, and the tyre specialists in the garage said that it is safe enough to have different tyres on the rear axle as long as both are well over he legal depth. But some places online claim otherwise.

Who is right? Do I need to go back, dump the remaining still-good rear tyre, and have another new Hifly fitted? I would not want to waste the money but if it is critical for safety I'll have to do it.

bazz26

I'd be more concerned about the quality and performance of the Hilfy tyre on the car. If you can afford it then I'd get rid of it and put on a similar tyre or at least one similar in quality and thread pattern to the one on the other side.

Wheelnut

Almost everybody will tell you it's wrong but I wouldn't worry about it, after all we're not talking Ferrarri or Porsche here.

CiniO

I wouldn't feel comfortable having two different tyres within one axle.
In most countries such setup is illegal.
In Ireland it's OK, but as above - I wouldn't be happy with such setup on my car.

mickdw

The hifly is likely to be your biggest issue.
Its a kia picanto so I would assume good quality tyres in those sizes are not so expensive.
Id stick 2 good tyres on the rear.

GTE

Personally,

I have had to run two different tyre brands on the front axle for the past couple of months. This is purely down to finances however my recent switch over to two new tyres on the front was done out of safety - see point 1.

1) In dry conditions, I do not mind the tyres being different brands however in the wet, taking individual tyres performances out of the equation, my biggest worry was the tread depth difference and what effect it would have in destabilising the car going through deep water. The older (but better quality) front tyre did reach about 2mm tread depth.

2) Just a second point, the new tyre that I had on the front was to replace a punctured one. It just so happens the replacement is a Hifly. I do not know which model but to be fair to it, it was fine. No serious issues in cornering. No major braking events to my name recently so I cant tell there. It is much better than the Event set of tyres which were on other cars in my family, terrible. That said, it performs well below my expectation in the cold which is what prompted my recent tyre replacement. The Hifly is now my spare tyre.

To hook back into point 1, now we should consider the individual tyre performance in the wet. I am not saying that a bad tyre is going to perform so badly in heavy water situations, or any situation bar snow/ice, that it is going to destabilse the car because I am not qualified to say that but as I think you are aware, it pays to have good rubber. So with that said, sorting out the rear tyres soon should be a good move.

I think you are fine in using the Hifly as a spare or at least aim to use it as a spare as you consider your options for the rear.

kerten

Picanto should have very narrow/small size tyres with easy to reach limits in an emergency.

I wouldn't reduce these limits for saving 100-120 quid for two tyres.

MichaelR

The other tyre on the rear is currently a Mohawk which is, as I am told, another budget brand. The front ones are now both new Uniroyal Rainexperts and that's about as good as one can get with this size apparently. They were the best in reviews f the stuff I found in three garages.

The size in question is 165/60 R14.

I definitely can;'t afford to remove the new Hifly and put two more Uniroyals on the back. The question is whether I need to replace the part-worn but still good Mohawk with a new Hifly so the two rear tyres match in wear (a difference of a day or two won't matter).

The car is of course a front wheel drive.

kerten

MichaelR wrote: »

The other tyre on the rear is currently a Mohawk which is, as I am told, another budget brand. The front ones are now both new Uniroyal Rainexperts and that's about as good as one can get with this size apparently. They were the best in reviews f the stuff I found in three garages.

The size in question is 165/60 R14.

I definitely can;'t afford to remove the new Hifly and put two more Uniroyals on the back. The question is whether I need to replace the part-worn but still good Mohawk with a new Hifly so the two rear tyres match in wear (a difference of a day or two won't matter).

The car is of course a front wheel drive.

You have two different tyres at rear with different limits due to compound/design/tread depth differences.

So if you reach these limits(aquaplanning resistance, lateral grip at fast turns, braking in wet/snow, etc), car can behave unexpectedly rear stability wise.

If you are aware of these limits of your current car/tyre combination, you can avoid dangerous situations by adjusting your driving in theory.

BTW, rainexperts are grippy tyres so be careful about limits of lateral grip as rear tyres may not cope up with same lateral grip of uniroyals if you push the car at the bends

GTE

MichaelR wrote: »

The other tyre on the rear is currently a Mohawk which is, as I am told, another budget brand. The front ones are now both new Uniroyal Rainexperts and that's about as good as one can get with this size apparently. They were the best in reviews f the stuff I found in three garages.

The size in question is 165/60 R14.

I definitely can;'t afford to remove the new Hifly and put two more Uniroyals on the back. The question is whether I need to replace the part-worn but still good Mohawk with a new Hifly so the two rear tyres match in wear (a difference of a day or two won't matter).

The car is of course a front wheel drive.

Mohawk are terrible. My friend had a remapped 3 series, about 170hp. Okay, that is miles away from your car but it would spin up in almost every gear, the wet was a joke and it just hardly seemed to wear given the driving. They seemed like the ever lasting gobstopper of tyres so I can't imagine the grip was great.

That said, maybe a new hifly and Mohawk as a spare? How is your spare doing?

I am a big cold weather tyre guy, but I honestly did not have any issues in the Summer/Autumn with the Hifly (195/65/15). It was fitted to the front with a heavy diesel lump. I would be interested in other comments on this thread

MichaelR

I'll check the spare but I think it is a space saver. However your explanation makes sense - if the Mohawk has bad grip AND does not wear off it might just hang out there as a source of potential trouble and perhaps I should replace it. I sort of assumed all budget tyres were the same. Will await some more comments though.

Not installing the Hifly and later getting two more grippy Uniroyals might have been a better option but too late now - besides I really do have financial limitations as the other car in the family, a Kia Cee'd, will need front tyres soon too... and the rear ones are BOTH good enough but different! And it was the official KIA dealer service who put one new rear on it a year and a half ago. I probably won't replace the two until at least one is worn though. But I'll try and get good brands for the front this time.

I'm trying not to push at the bends for completely unrelated reasons though - tyres won't do me much good if there is a person behind the bend... besides two tyres holding their grip might be better than all four losing it, especially as the grippy ones are on the drive+steer wheels?

MichaelR

Oh - and I did consider getting a set of winter tyres but for the few days when it's actually below zero in Ireland, I don't think it's worth the few hundred (even if I get the discs from a breaker), besides I don't really have a place to store them.

green123

MichaelR wrote: »

I'm trying not to push at the bends for completely unrelated reasons though - tyres won't do me much good if there is a person behind the bend... besides two tyres holding their grip might be better than all four losing it, especially as the grippy ones are on the drive+steer wheels?

i think most advice says that the best tyres should be on the back wheels.
maybe somebody on here can confirm that ?

650Ginge

green123 wrote: »

i think most advice says that the best tyres should be on the back wheels.
maybe somebody on here can confirm that ?

You are correct, best tyres should always be at the rear. The reason is to stop lift off over steer which particularly in fwd is very hard to recover.

colm_mcm

650Ginge wrote: »

You are correct, best tyres should always be at the rear. The reason is to stop lift off over steer which particularly in fwd is very hard to recover.

The ops car understeers at the best of times. Id have the good ones at the front contrary to whats recommended.

GTE

colm_mcm wrote: »

The ops car understeers at the best of times. Id have the good ones at the front contrary to whats recommended.

Though given a wet road, the poorer performance of a bad tyre or low tread tyre on the rear could cause oversteer issues.

I would pick understeer over oversteer any day.

I am not making comments against the OP tyre situation, just the principal,

stoneill

MichaelR wrote: »

Oh - and I did consider getting a set of winter tyres but for the few days when it's actually below zero in Ireland, I don't think it's worth the few hundred (even if I get the discs from a breaker), besides I don't really have a place to store them.

Save your money from winter tyres and buy good quality all year round tyres instead.

MichaelR

OK, looks like you have me convinced on replacing the final rear tyre with another Hifly to match the one already fit. However, I will not dump the new Hifly to install two more Uniroyals.

Now the only question is whether I should switch Hiflys to the front putting Uniroyals to the rear. I've been reading up on this, including this very forum http://www.boards.ie/vbulletin/showthread.php?t=2056472387 . I am thinking of leaving the Uniroyals on the front because:

- The car is very short and light, so losing the back into a swing seems like less of a possibility than understeer or not enough braking.

- The car is most likely heavier on the back and lighter on the front, its engine (which provides front weight on bigger cars) being a mere 1.1L. So the front tyres have less weight on them while they are used for driving AND steering AND braking. They need all the performance they can get.

- The Uniroyals are likely to wear slower under similar conditions (though there is some disagreement about that) while there is heavier wear on front tyres generally. So there wil be a better chance of replacing all 4 at the same time if the Hiflys go on the back.

- And also, the common Irish wisdom is to have best tyres on the front so, in case there is an accident and an insurance claim, "you did it wrong so it's your fault" will be a more likely statement if the best tyres go on the back.

Is this correct or did I miss something?

kerten

MichaelR wrote: »

OK, looks like you have me convinced on replacing the final rear tyre with another Hifly to match the one already fit. However, I will not dump the new Hifly to install two more Uniroyals.

Now the only question is whether I should switch Hiflys to the front putting Uniroyals to the rear. I've been reading up on this, including this very forum http://www.boards.ie/vbulletin/showthread.php?t=2056472387 . I am thinking of leaving the Uniroyals on the front because:

- The car is very short and light, so losing the back into a swing seems like less of a possibility than understeer or not enough braking.

- The car is most likely heavier on the back and lighter on the front, its engine (which provides front weight on bigger cars) being a mere 1.1L. So the front tyres have less weight on them while they are used for driving AND steering AND braking. They need all the performance they can get.

- The Uniroyals are likely to wear slower under similar conditions (though there is some disagreement about that) while there is heavier wear on front tyres generally. So there wil be a better chance of replacing all 4 at the same time if the Hiflys go on the back.

- And also, the common Irish wisdom is to have best tyres on the front so, in case there is an accident and an insurance claim, "you did it wrong so it's your fault" will be a more likely statement if the best tyres go on the back.

Is this correct or did I miss something?

If you have no idea about your cars limits and are entering same bend at different speeds everyday without noticing, then I would put better tyres to back to prevent random oversteering(losing back of the car)

But having good tyres in front means better braking and general traction. You may need this more if you drive with care.

dr.fuzzenstein

MichaelR wrote: »

The other tyre on the rear is currently a Mohawk which is, as I am told, another budget brand. The front ones are now both new Uniroyal Rainexperts and that's about as good as one can get with this size apparently. They were the best in reviews f the stuff I found in three garages.

The size in question is 165/60 R14.

I definitely can;'t afford to remove the new Hifly and put two more Uniroyals on the back. The question is whether I need to replace the part-worn but still good Mohawk with a new Hifly so the two rear tyres match in wear (a difference of a day or two won't matter).

The car is of course a front wheel drive.

Lift off oversteer is not so bad, but if you're going through a corner and have to brake hard, the crappy tires at the back will lose grip and you will end up doing a 180. Believe me, it happened to me.

justsomebloke

What type of spare tyre do you have? is it a space saver or full tyre. If a full tyre what make is it?

MichaelR

Checked the spare - unexpectedly it is a full size and at the legal depth limit, so I can put the Hifly on the spare now. Ordered two more Uniroyals.

The only worry is that the spare disk looks rusty. But on a 2010 car it should not be really bad? Going for a brand new disk is too much I'd say. (The car has steel disks not alloys). Not sure I am using the right term here - disk? rim? anyway the metal part of the wheel

colm_mcm

You'll get surface rust but don't worry about it.

MichaelR

Realized I could still get a second Hifly and use the pat worn Mohawk on the spare. It would save 100 Euro compared to a new pair of Uniroyals. However I'll probably go for max safety now, ok it's a small car with average passive safety ratings, so let it have all it can...

Supergurrier

I have Goodyear F1's on the front and Nexen's on the back.

It's fine tbh

grainnewhale

Cant imagine a picanto is going to be throwing the arse around that much. the tyres on it will be fine. relax.

biko

I don't see any reason to worry once they are the same (correct) size.

TheBully

kerten wrote: »

You have two different tyres at rear with different limits due to compound/design/tread depth differences.

So if you reach these limits(aquaplanning resistance, lateral grip at fast turns, braking in wet/snow, etc), car can behave unexpectedly rear stability wise.

If you are aware of these limits of your current car/tyre combination, you can avoid dangerous situations by adjusting your driving in theory.

BTW, rainexperts are grippy tyres so be careful about limits of lateral grip as rear tyres may not cope up with same lateral grip of uniroyals if you push the car at the bends

Its a bloody Kia Picanto, Not a McLaren SLR, the car will be fine

TheBully

MichaelR wrote: »

Realized I could still get a second Hifly and use the pat worn Mohawk on the spare. It would save 100 Euro compared to a new pair of Uniroyals. However I'll probably go for max safety now, ok it's a small car with average passive safety ratings, so let it have all it can...

are u paying €100 for a 165/60x14 budget brand tyre???
€50 in max Tyres in Mayo

MichaelR

Uniroyal is not a budget brand and is 75 per tyre. Hifly is indeed 50 Euro per tyre.

I now have: 2x Uniroyal new on front, 1xHifly new and 1x Mohawk part worn on back. And a spare that has a fully worn tyre.

My options

- Do nothing (0 Euro, already out of the list)
- Put Mohawk on spare, add another new Hifly on back (50 Euro)
- Dump Mohawk, move existing new Hifly to spare, put two new Uniroyal on back (2x75 = 150 Euro)

I am probably going with the last option, but still thinking.

TheBully

MichaelR wrote: »

Uniroyal is not a budget brand and is 75 per tyre. Hifly is indeed 50 Euro per tyre.

I now have: 2x Uniroyal new on front, 1xHifly new and 1x Mohawk part worn on back. And a spare that has a fully worn tyre.

My options

- Do nothing (0 Euro, already out of the list)
- Put Mohawk on spare, add another new Hifly on back (50 Euro)
- Dump Mohawk, move existing new Hifly to spare, put two new Uniroyal on back (2x75 = 150 Euro)

I am probably going with the last option, but still thinking.

Put on 1 hifly on the back, save yourself 100 euros!

kerten

TheBully wrote: »

Its a bloody Kia Picanto, Not a McLaren SLR, the car will be fine

While I get your point, are you saying it is not possible to reach limits of grip in a picanto with 165 tyres ?

I meant it is all about driving according to limits of the car here. Not every driver on the road is aware of it in these days.

I am not telling OP the buy 2 more uniroyals to be safe. I am telling him to buy 2 more uniroyals if he wants to have higher limits of grip than current state of car.

You generally reach these limits once or twice in your life but I prefer to have higher limits when it happens.

I have driven a car with 4 bald tyres in any weather condition for 6 months without an accident(stupid but there were no other options). But I was super cautious during this 6 months to avoid any emergency manuever/breaking for the obvious reason.

It is all about being aware of risks associated with your choice. I think OP has more than needed data here regarding choices here already.

GTE

kerten wrote: »

You generally reach these limits once or twice in your life but I prefer to have higher limits when it happens.

This is a big point for me.

So many people wont need to reach the limits of their tyres in their lifetimes if they have a nice uneventful driving life. To be slightly flippant, there are so many complaints about slow drivers on the forum that we know this to be the case. Then again, there are very rapid drivers out there where you could think "how close to the limit are they really?"

Personally, I completely misjudged a section of unfamiliar road a couple of months ago. I was first fooled by those damn 80kph signs on a decent road and then I was met by a near 90 degree turn on a narrowing path. This is the first time my ABS was used for safety reasons in all my 5 years driving (I know I am still a youngin). I was very grateful I had a set of Hankooks on over Mohawks or Events.

There have also been times that I have driven through heavy standing water on a motorway and wondered "if I had less tread, I would be in trouble here if I had to take avoiding action" so that is where even the slow drivers would have an issue. Even putting tread to the side, how about an individuals tyres water dispersion characteristics or its compounds ability in the wet?

I would like to find out what proportion of slides and skids are down to the tyres limit being reached.

A poster or two mentioned here how it is only a Picanto but I had a set of Event tyres on a 1.6 Corolla and the front would slide around in the wet as if it was ice and that is not pushing it by any means. A set of Coopers turned to rubbish when the cold set in on my own car.

I think that a better appreciation is needed by motorist in general (not necessarily here) for how any brand tyre can keep the car on the road but it is when the tricky stuff happens that bad quality shows up and that each tyre will have a different ceiling of competence. That said, I am sure I am not on the "best" tyre for stopping distances or wet competency but I am not on bad ones either.

It just takes one need for hard braking to show up a tyre as being a pile of junk that never had a chance of stopping you in a safe distance when the going gets tough.

MichaelR

Well I selected the Uniroyals based on reviews for wet competency. I did consider all seasons but ice is only a few days a year while wet is all year, and everyone says dedicated 3-season wet tyres dp beter than the all seasons in wet - and the Uniroyal Rainexpert was recommended for the wet, too. One review even says it can hold its own on ice, though not sure if I can trust the review. The downsides were noise, fuel efficienty (but how bad can tyres make fuel efficiency?) and, by some reviews, they wear fast, other reviews disagree, I'll just have to see.

The final shortlist had them and Coopers. judging by the experience with Coopers that bbk mentioned, I made the right call...

kerten

MichaelR wrote: »

Well I selected the Uniroyals based on reviews for wet competency. I did consider all seasons but ice is only a few days a year while wet is all year, and everyone says dedicated 3-season wet tyres dp beter than the all seasons in wet - and the Uniroyal Rainexpert was recommended for the wet, too. One review even says it can hold its own on ice, though not sure if I can trust the review. The downsides were noise, fuel efficienty (but how bad can tyres make fuel efficiency?) and, by some reviews, they wear fast, other reviews disagree, I'll just have to see.

The final shortlist had them and Coopers. judging by the experience with Coopers that bbk mentioned, I made the right call...

You picked correct tyre. I have used rainexperts on a 1.0 yaris similar size of yours for 30k km. They never let me down in emergency situations or when I pushed them intenionally. I couldn't aquaplane them at all even I accelerated into puddles for testing. There was almost no difference betwen wet and dry grip but they are noisy as you already know

stoneill

What sort of driving are you doing that you are getting understeer and oversteer in a picanto?
If you are having those issues on a standard road car, then it's not the car you need to look at!