D4, went from 18's to 19's, now trobleshooting a lumpy ride

[mjbsx]

I'm trying to troubleshoot a possible issue with my '12 D4 (48,000km), would appreciate any opinions/experience.

I bought the D4 secondhand (dealer) in Dec.
Almost immediately I replaced the stock 18's, with a set of (secondhand - but brand new condition) original Landrover '19's and brand new Goodyear Wrangler's (I wanted a different look) - I swear this move has changed the ride, it's subtle, but its not as smooth as what it was.

I only drove the 18's for a few days, but I just don't remember the ride being what it is now (see below).
I recall it being very smooth - everything you read about RE Discos.

Since I had the 19's/Wrangler fitted I find the ride of the car, a little 'lumpy', the best way to describe the ride/rolling feeling is that a wheel or tyre is misshaped or out of balance. It's kind of a regular, rolling motion, more noteworthy from 70km/h and above. Seems to get less noticeable the more heavily loaded the car is.

FYI: I've come out of a Nissan Murano, which frankly was an incredibly smooth ride (engine/transmission, steering wheel feedback etc). And was way smoother to drive than the Disco.

In terms of diagnosis:
Ive driven on the smoothest possible roads (to assess), had multiple wheel balances, and recently Landrover has checked and balanced all wheels (thats complicated), and their view was that the ride on the 19's is 'normal'.

Can't for the life of me think why these wheels/tyres would not offer as good a ride as stock 18's.

My next steps to try and work out whats going on:
1. Drive another Disco on 19's as a comparison (maybe this is just how these things roll/drive)?
2. Will refit the original 18's and see if it rolls/rides any differently.
3. Get a tyre guy to assess if the 19's or tyres are damaged/faulty
4. Could air suspension cause an odd feeling ride (not sure), but there are no signs of that.

Any experience/opinions would be great.

ps. Otherwise the car has been checked over.
Recently serviced, and it's end of warranty check done (front diff, left wheel bearing and water pump seal replaced).

thanks

[Nicky]

What other mods does this vehicle have?

[jon3950]

The ride on 19"s will always be harsher than on 18"s. What pressures are you running?

Cheers,
Jon

[Graeme]

19" generally provide a harsher ride than 18" due to the shorter sidewalls. I replaced my 19" with LT 17" which gave a softer ride even though LT. However I wouldn't describe the 19" ride as lumpy, only that small bumps are more readily felt.

[TDV6]

The tyre may be out or round, one of my Bridgestones is but not by much. The easiest way to check is to have a tyre shop take them off the car and then spin them.

As has been previously said lower sidewall height will have a harsher ride.

Ryall

[mjbsx]

Thanks all.

1. No other mods to the car
2. Tyre pressure - good point, will check next time I'm out.
3. Getting them off the car to be checked (for round) is a good idea, that might be my next step. Only downside, being I imagine they'll need to be re-balanced.

[letherm]

Thanks all.

3. Getting them off the car to be checked (for round) is a good idea, that might be my next step. Only downside, being I imagine they'll need to be re-balanced.

I don't know if it's possible with these cars but any easy way to check if a tyre is out of round is to jack it up, spin it and hold a piece of chalk close to the tread as it spins until you just touch the tyre.

[Tombie]

Put the 18s back on - better rubber choice, cheaper for Tyres and smoother ride

Saying that, pressures are important...

And, how are the shocks? How far has it driven/towed?

[mjbsx]

MY12, it's done 48,000km, never been offroad/towed.
I'd expect that's a bit early for shocks?

I'll check ideal pressures and make a change though.

[jon3950]

I'll check ideal pressures and make a change though.

That should be your first step. Start with the placard pressures as they will give you a decent ride if there are no other problems.

An out of round tyre or rim should have been picked up while balancing, but if the pressures don't fix it then worth checking again.

What you describe sounds like a possible out of round problem but the fact that it improves when you increase the load suggests pressures may be too high to me.

At 48k all your suspension should be just fine, but of course with a second hand car something may have happened that you don't know about. Eliminate the basics first.

Agree with Tombie though, these things are nicer on 18"s.

Cheers,
Jon