Had our poor CRV into local garage recently to sort out rubbing rear brakes. No biggy, we knew discs had a bit of a lip and pads needed replaced.

They also did something with the tyres, fitted new Forceum Pentas to the front and moved existing Toyos from the front to the back.

Since then the car has always felt like it’s labouring, revs and speed seem normal enough/par for the course but the engine note just doesn’t sound happy and it doesn’t doesn’t seem as responsive as it used to be.

Finally, it ‘thrums’ a bit once you get up to 70ish.

Could this just be cheap nasty tyres, or could they have knocked tracking out or something? I don’t want to take it back yet until I’m sure I’m not just being stupid, maybe it’s entirely normal for a car to ‘sound’ different when you fit new tyres…

Ta

You can get different road noise from the tyres and they they will have different feel on the steering wheel.

But I don’t think the engine noise and performance should be effected by tyres.

Have you felt the wheels for excess heat after a run? Sound like the brakes are still binding.
Different tyres can be draggier but not to the extent you are suggesting in my experience

Aye, sounds more like a brake problem.

Can you get them to fit rim brakes instead?

Sound like the brakes are still binding.

This.

Rotating tyres on fwd cars isn’t the ‘done thing’ anymore. Odd that the garage did it at all.

Secondly, your new tyres are not like for like with the outgoing Toyos (I’m guessing they’re something like Proxes CF2). Did you specifically ask for budget tyres/at a max price?

Your problem does sound mechanical, but I’d at least check the pressures, if you do go back to garage also get them to check the wheel balancing.

How does Honda’s AWD system work? If it’s a simple viscous coupling, the ever so slight difference in rolling diameter between the new fronts and probably smaller rears might be making the rear axle engage – adding to the drag the engine has to overcome.

They also did something with the tyres, fitted new Forceum Pentas to the front and moved existing Toyos from the front to the back.

New tyres should go on the rear axle really.

Anyway as above my bet would be the brakes still binding. Carefully touch each of the wheels after a drive. They should be nothing more than very slightly warm.

How does Honda’s AWD system work?

I think it’s a Haldex style clutch system, so disengaged most of the time and only engages when ABS sensors detect difference in wheel speeds.

https://www.awdwiki.com/en/honda/

Can you get them to fit rim brakes instead?

Bravo, sir!

Scotroutes wins

But this does sound like sensors having a fit due to wheel size differences.

Fitting 2 new tires to an AWD with a viscous or haldex is not a good idea.

FWIW I just had to have a new caliper on my mk2 crv, same symptoms, thrumming on A road / motorway speeds, baking hot wheel. Old caliper had simply seized.

How does Honda’s AWD system work? If it’s a simple viscous coupling, t

edit: hydraulic clutch activated when slip detected, not quite haldex, it uses pumps driven by both diffs to engage the coupling, similar end result

edited because I posted cobblers

Fitting 2 new tires to an AWD with a viscous or haldex is not a good idea.

Haldex style is engaged by ABS sensors, so switched off most of the time. I had a 1st gen Haldex for 10 years on my V6 4Motion Golf, never bothered changing all 4 tyres at the time, just replaced which ever one needed doing.

Is still bad practice.

If the abs sensors are anything like as reliable as my MK4 golf…they would be switched off most of the time also.

But modern abs sensors can and do detect differences in tire od. If it feels like a wheels slipping it can cut the power or apply the brake……

But yeah if you have had sticking brakes cleaned up it’s likely that as you generally don’t just clean them and it’s ok. But the mixing tires on modern awd being bad is a thing.

Can you get them to fit rim brakes instead?

Yes yes, bravo 😁

Good stuff otherwise as well folks, thanks.

Will check diameters, can printed diameters on car tyres be trusted? e.g. if all 4 tyres have same printed diameter is that enough, or will tyre wear/brand make a big enough difference?

The tyre pressure indicator has been lit since we had the tyres swapped but it has traditionally been a bit fickle so I’ve learned just to ignore it and check tyres periodically at filling stations.

The tyre pressure indicator has been lit since we had the tyres swapped

That might be a clue to the problem. Some of them, generally the ones that don’t actually have a pressure monitoring valve, work by detecting a difference in wheel speed via the ABS sensor. As the tyre goes flat and looses a little diameter. If the same mechanism triggers the 4WD, as suggested above, may be related.

The tyre pressure indicator has been lit since we had the tyres swapped but it has traditionally been a bit fickle so I’ve learned just to ignore it and check tyres periodically at filling stations.

My spidey sense is now going awoooga awoooga …..

That will also be run off the abs sensors on a Honda which is telling me to check thoughoally that you dont have a mismatch.

No printed numbers on tires can’t be trusted unless it’s the same tire…… Think 2.4 continental Der Barron Vs maxxis 2.4 nothing like the same ….

Will check diameters, can printed diameters on car tyres be trusted? e.g. if all 4 tyres have same printed diameter is that enough, or will tyre wear/brand make a big enough difference?

They sometimes have slightly different shapes to the sidewalls, but the outer diameter should be fairly consistent as they have belts under the tread to give them their square shape, as well as the plys that go side to side (bike tyres a crossply, cars are radial, but that just refers to the angle they cross at).

Wear can make a difference (about 1%).

The tyre pressure indicator has been lit since we had the tyres swapped but it has traditionally been a bit fickle so I’ve learned just to ignore it and check tyres periodically at filling stations.

Tyre pressure also affects the rolling diameter, might be worth double-checking them whilst cold and sat on your driveway. You could stick a few extra PSI in the rear tyres to increase their diameter just to test the theory and see if the problem goes away.

That might be a clue to the problem. Some of them, generally the ones that don’t actually have a pressure monitoring valve, work by detecting a difference in wheel speed via the ABS sensor. As the tyre goes flat and looses a little diameter. If the same mechanism triggers the 4WD, as suggested above, may be related.

Yep, ours are wheel speed sensors. Would it be reckless to test drive with ABS turned off? There’s a tempting looking button down beside the steering wheel that I’ve always wanted to press…

My spidey sense is now going awoooga awoooga …..

😂

The tyre pressure indicator has been lit since we had the tyres swapped but it has traditionally been a bit fickle so I’ve learned just to ignore it and check tyres periodically at filling stations.

Get a proper tyre pressure gauge of your own and keep it in the car. The ones at petrol stations cannot be trusted.

Yep, ours are wheel speed sensors. Would it be reckless to test drive with ABS turned off? There’s a tempting looking button down beside the steering wheel that I’ve always wanted to press…

I wouldn’t have thought that would make a difference, the sensors will still be switched on, the pumps driving the center diff will still be on, it’s just the valves on the ABS pump that won’t move.

The off button is for off-road/ice where the wheels will lock up and it’s better to keep them that way because ABS on ice is scary as essentially it means the brakes don’t work!

There’s an off-road ABS system now which biases the calculation more towards locking up until it senses some grip then it goes back to normal ABS.

They sometimes have slightly different shapes to the sidewalls, but the outer diameter should be fairly consistent as they have belts under the tread to give them their square shape, as well as the plys that go side to side (bike tyres a crossply, cars are radial, but that just refers to the angle they cross at).

You say that and I’d agree with most points but I’ve pulled two different branded tires and put them on top of each other and noted a visual variance between them

Haldex states +/-4% Audi state +/-2% for quattro and honda don’t seem to have a. Number in public domain but owners groups siting 1.5mm across diameter difference -but that seems awfully small tollerance to me

To confirm if the caliper is still sticking go for a 15min drive, then jump out and see if the wheel with the binding caliper is noticeably warmer than the other 3.

It is not unheard of to find the wrong size ie aspect ratio fitted , tyre diameter for rim fitment
is quite difficult to get wrong (barring some rare metric sizes) so do check the aspect ration – 215/<65>/17 for example is not the same as 215/50/17 , it does normally look wrong too.
Also the TPMS system light on will be an MOT fail so needs sorting.

You say that and I’d agree with most points but I’ve pulled two different branded tires and put them on top of each other and noted a visual variance between them

Sorry, wasn’t intentionally disagreeing with you just crossed posts.

Surprised they could be that far out between brands though.

2% makes sense (more than enough to allow for a worn Vs new tyre), 1.5mm seems a ludicrous tollerance unless all 4 tyres wear out very evenly?

I think we have a bingo!

Front tyres noticeably warmer than rear (perhaps that’s normal). Centres of alloy wheels all felt the same after 15 minutes.

However, a quick check of wheel diameters (I tried circumference but Ikea tape measure not long enough…) suggests 69.5cm diameter on front and 71cm rear, 2% difference?

Next check is obviously to check pressures etc. and maybe artificially increase diameter as per spoon’s suggestion.

Interesting stuff!

From recollection when working in a Ford main dealer, i was given an AWD Kuga to look at for an AWD warning coming on intermittently and sometimes dropping in to 2wd and back out. Issue had only arisen since a local tyre place fitted 2 new budget tyres on the rear, with it having Goodyears on the front at 6mm with even wear. They had moved the front tyres on 6mm from the rear to the front. Anyhow, after several roadtests and much datalogging on the transmission, found out from Ford technical that is was down to the minute difference in rolling diameter that was triggering the issues. He came back the day after with matching tyres and we recalibrated the TPMS, never saw him again…

It seems a shame you can’t recalibrate ABS computer to a ‘new normal’ difference in front and rear.

ABS shouldn’t care really, I’d have thought the triggers to the abs pump and the haldex unit will be predominantly based on relative acceleration of an individual wheel, not their average relative speed (which the TPMS will care about).

I run decent tyres on all my vehicles. Swapping between winters and summers.

I had Michelin PS4s on my I30N before selling it, took them off the day I dropped it off at Webuyanycar, replacing them with ‘quality’ tyres from Blackcircles.

They were awful. Night and day difference as soon as you got a bit close to the edge.

If you didn’t drive enthusiastically I doubt you’d actually notice the difference.

It was a combination of wet roads, tight bends and not expecting the tyres to be so hard.

I can tell the difference between different tyres as changes in rolling resistance cause appreciable differences in the amount of power used – easier to see in an electric car telling you how many watts per km, and 5,6 % enough to kaibosh AWD?

It seems a shame you can’t recalibrate ABS computer to a ‘new normal’ difference in front and rear.

I do a “reset” on the TPMS on the Skoda when we have new tyres fitted.

Rotating tyres on fwd cars isn’t the ‘done thing’ anymore

Why not? I do it on mines, usually every 10k miles (Assuming a full set of tyres last 20K). Means you always have a good tread for the front, which has to deal with power, steering and braking so good front axle grip is paramount.

I know there’s people out there that think its a bad idea as having more worn tires on the rear can make the back end go loose in certain situations like lift-off oversteer, but I’d rather have oversteer than understeer given the circumstances, you still have more control.

Rotating decent tires is still way better than just bunging on 2 new Chinese ditchfinders, which is what most people/garages seem to do these days…