Anyone running 550-19 tyres?

[M2M]

If yes, please post some photos. I'm interested to see what they look like on a car.

[Domino]

Look at my vatar

[M2M]

Originally Posted by Domino

Look at my vatar

Thanks. Did you notice any improvement in ride or handling compared tp standard size 19" tyres?

[CarlG]

Here's my pickup with 550R19 radials (By comparison, my avatar has 475-19 Firestone bias ply tires)

[M2M]

Those radials look fine and I'm sure ride and handling improves but I was more thinking of 550-19 bias ply as they are a lot cheaper plus they are wider in diameter than the radials. As you all know, the wider the diameter, the bigger the "poor boy" overdrive effect is; my car I think has standard gearing and an overdrive transmission is not on the cards.

So my question is:

What would the advantages or disadvantages be from changing 475-19 bias ply to 550-19 bias ply?

[Synchro909]

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Originally Posted by M2M

Those radials look fine and I'm sure ride and handling improves but I was more thinking of 550-19 bias ply as they are a lot cheaper plus they are wider in diameter than the radials. As you all know, the wider the diameter, the bigger the "poor boy" overdrive effect is; my car I think has standard gearing and an overdrive transmission is not on the cards.

So my question is:

What would the advantages or disadvantages be from changing 475-19 bias ply to 550-19 bias ply?

In theory, the 5.50 tyres will bump the overall wheel size from 28.5" to 30", about a 5% higher gearing. In addition, the larger tyres will have a larger contact area with the road. Road holding will be better. I have run 5.25X21" on my '29 and noticed a definite improvement. So much so that I think radials would have to be pretty fantastic to justify the price.

[M2M]

Originally Posted by Synchro909

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In theory, the 5.50 tyres will bump the overall wheel size from 28.5" to 30", about a 5% higher gearing. In addition, the larger tyres will have a larger contact area with the road. Road holding will be better. I have run 5.25X21" on my '29 and noticed a definite improvement. So much so that I think radials would have to be pretty fantastic to justify the price.

Thanks for the info.

The 550-19 bias-ply tyres I'm considering are just over 31" diameter and tread width is 4.3". The 475/500-19 Firestone are just under 30" and tread width is 3.9". There's not much of a difference in price.

[Y-Blockhead]

Originally Posted by M2M

The 550-19 bias-ply tyres I'm considering are just over 31". The 475/500-19 Firestone are just under 30". There's not much of a difference in price.

With stock gearing (3.78) @ 2200 rpm, mathematically you will gain ~2-3 mph.

[J Franklin]

I doubt you will notice any real gain in ratio, but you will like the ride.

[Curtis in MA]

I thought 4.75 was the width, why would changing to 5.50 change the diameter?

[M2M]

Originally Posted by Curtis in MA

I thought 4.75 was the width, why would changing to 5.50 change the diameter?

Tyre makers also increase the sidewall height when they increase the tread width to keep the same aspect ratio, so the tyre diameter increases. Same happens with modern radial tyres, except radials are often made in various aspect ratios (ie. low profile), so it's possible to increase tread width without increasing the diameter. Bias ply are made only in the aspect ratio of 100.

[M2M]

Originally Posted by Y-Blockhead

With stock gearing (3.78) @ 2200 rpm, mathematically you will gain ~2-3 mph.

Hmmm, isn't that gain similar to the gain achieved changing from 3.78 to 3.54 (without changing tyres size)?

[Y-Blockhead]

Originally Posted by M2M

Hmmm, isn't that gain similar to the gain achieved changing from 3.78 to 3.54 (without changing tyres size)?

Just about, 3.41 mpg @ 2200 rpm for the gear change.

[updraught]

Some of those tyres can be quite heavy (maybe 6 ply?). More weight on the outer edge of the wheel. Takes more to stop the wheels from spinning before the car can be braked. The wheels are spinning slower so there is less friction in your brakes. This may or may not be better for drum brakes? Sure as heck isn't better for discs.

A 3.27 ring and pinion and speedo thingy can be sent in medium flat rate box from Berts.

[captndan]

Mine too.

[JohnLaVoy]

I'm running the Excelsior tires and I think they are 600X19 but you get a 50,000 tread mile warranty on these.

[M2M]

Originally Posted by JohnLaVoy

I'm running the Excelsior tires and I think they are 600X19 but you get a 50,000 tread mile warranty on these.

Looks like they're the radials discussed above. Sure they're not 550-19? I would have thought 600-19 is too big for Model A rims.

[M2M]

Originally Posted by updraught

Some of those tyres can be quite heavy (maybe 6 ply?). More weight on the outer edge of the wheel. Takes more to stop the wheels from spinning before the car can be braked. The wheels are spinning slower so there is less friction in your brakes. This may or may not be better for drum brakes? Sure as heck isn't better for discs.

A 3.27 ring and pinion and speedo thingy can be sent in medium flat rate box from Berts.

I'll check out the weight of bias-ply 550-19 but I doubt slightly heavier tyres will break the camel's back when it comes to stopping.

Main reason I'm interested in 550-19 is for the improved road holding people have mentioned; the overdrive effect is just an added bonus.

[updraught]

>>I'll check out the weight of bias-ply 550-19 but I doubt slightly heavier tyres will break the camel's back when it comes to stopping.

Depends how marginal your brakes are to start with. If you have hydraulic brakes you might have some braking power up your sleeve. And the tyres won't touch the brake rods.

I'm just giving a heads up that bigger tyres and more unsprung weight is not good for braking.
My everyday car came with 30 inch tyres. I run 31 inch with alloy wheels. I went to a very soft disc pad to bring the brakes back to standard.

When you are next in Russia, hop across to Iceland and hire an Arctic Truck from the factory.


>>Looks like they're the radials discussed above. Sure they're not 550-19? I would have thought 600-19 is too big for Model A rims.

650-19 radials are 30.9 inch. 6.6 inch section width. They are all too wide for the 3 inch rim.

[M2M]

Originally Posted by updraught

I'm just giving a heads up that bigger tyres and more unsprung weight is not good for braking.
My everyday car came with 30 inch tyres. I run 31 inch with alloy wheels. I went to a very soft disc pad to bring the brakes back to standard.

When you are next in Russia, hop across to Iceland and hire an Arctic Truck from the factory.

Since you brought up Russia; they there don't seem to agree with you about tyre size, see:

gaz-a-karakumy.jpg

gaz-a-karakumy1.jpg

karakumy.jpg