Alfa Romeo 4C Forums banner

1 - 14 of 14 Posts

·
Registered
Joined
·
376 Posts
Discussion Starter #1 (Edited)
Time for tires and I was thinking a bump up to 255 35 19's to fill out the rear arch and protect the wheel a little more? If needed, possibly adding a 10MM spacer to help fill in the gap/push the offset?

Wondering if anyone has bumped up the tire width on the OEM LE wheel yet and if there's any rubbing issue with the suspension (w/o the spacer)?
 

·
Super Moderator
2015 4C Launch Edition
Joined
·
4,053 Posts
I have 245s on mine and no issue without spacers. Pretty sure 255 will clear also but depends on specific tire brand and model....I have Michelin PSS. The inner liners are somewhat flexible when heated with a heat gun if you need to manipulate them to get clearance.More importantly what are you running on the front. If stock wheels I would stick with 215 max since it is a 7" rim. A 225 will fit but over sized and will not be good for handling. Tire Rack has a good write up about selecting tire widths based on rim width. In short....tread width ON THE GROUND should be no greater than rim width. If wider it will lift the edges of the tires and handling goes to hell. Going in the other direction....slightly narrower tread width than rim width is good too....that is why ALFA put a 205 width tire in the front.
 

·
Registered
Joined
·
16 Posts
I have 245s on mine and no issue without spacers. Pretty sure 255 will clear also but depends on specific tire brand and model....I have Michelin PSS. The inner liners are somewhat flexible when heated with a heat gun if you need to manipulate them to get clearance.More importantly what are you running on the front. If stock wheels I would stick with 215 max since it is a 7" rim. A 225 will fit but over sized and will not be good for handling. Tire Rack has a good write up about selecting tire widths based on rim width. In short....tread width ON THE GROUND should be no greater than rim width. If wider it will lift the edges of the tires and handling goes to hell. Going in the other direction....slightly narrower tread width than rim width is good too....that is why ALFA put a 205 width tire in the front.
Thanks for the response. I’m getting Pirelli p zeros for the rears in 255 35 19 to replace my worn out 235 35 19s. The front ones are still stock p zeros 205s so I figured this could work well. No spacers.
 

·
Registered
Joined
·
102 Posts
Thanks for the response. I’m getting Pirelli p zeros for the rears in 255 35 19 to replace my worn out 235 35 19s. The front ones are still stock p zeros 205s so I figured this could work well. No spacers.
Bridgestone Potenza s007a will work too. I am getting those this Friday to see if they grip a bit better than Pirelli’s.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
310 Posts
Time for tires and I was thinking a bump up to 255 35 19's to fill out the rear arch and protect the wheel a little more? If needed, possibly adding a 10MM spacer to help fill in the gap/push the offset?

Wondering if anyone has bumped up the tire width on the OEM LE wheel yet and if there's any rubbing issue with the suspension (w/o the spacer)?
Don't! I had my alignment completely screwed because of 255/35/19 in the rear. I know you can adjust it, but it really was dangerous. It also looks way to thick. Go for a 255/30/19
 

·
Registered
Joined
·
746 Posts
Don't! I had my alignment completely screwed because of 255/35/19 in the rear. I know you can adjust it, but it really was dangerous. It also looks way to thick. Go for a 255/30/19
Wondering how the alignment setup would be that drastically offset with a relatively slight tire height differential (30 vs 35 profile) when the width/tire patch would be the same at 255mm?
TIA.
 

·
Super Moderator
Joined
·
14,690 Posts
Wondering how the alignment setup would be that drastically offset with a relatively slight tire height differential (30 vs 35 profile) when the width/tire patch would be the same at 255mm?
TIA.
Wondered that too - other than changing a miniscule amount of toe for camber and altering the caster slightly (due to rake - but it is so slight over the length of the wheelbase).
 

·
Registered
Joined
·
2,198 Posts
Stock:

205/40ZR18 /Front
235/35ZR19 /Rear

Plus One tire upgrade:

Why do we create new problems out of existing solutions and upgrades?

A no-wheel-change Plus One tire upgrade looks like this (which essentially maintains tire sidewall height, but throws more tire meat into tread width)

107929


Those numbers fatten the tire and just about keep ride height the same. This is a "Plus One" upgrade. This will jive with whatever alignment you have. Grip goes up. Footprint better. Dynamics same or better. For decades, this was filed under 'no brainer' as an upgrade.

Now, seemingly ''ok'', but NOT in the spirit of tire upgrades, some have simply bumped up the first number (205 to 215 and 235 to 255 without changing the aspect ratio (keeping 40 and 35 front and rear). Generally, this is a no-no when you can do a Plus One on a performance oriented car. This option has been done. It even looks good. The sidewall rises, the sidewall (equal tire to equal tire) is more compliant, so you should (generally) lose some sharpness, boost vehicle height and soften the ride. Again, I get why people do this. Also, it allowed many to tap into certain tires that otherwise might not have been available, so there wes an ROI for the investment in a taller tire that usually is a loss overall. If the Plus One option isn't possible, then this is a fall back, but the Plus One exists!

Spacers:

If you want to bump the tires/wheels out, to reduce the offset of the wheels, you need to add spacers regardless of whether you take a Plus One approach (above) or some other solution, and after looking at such changes over 4+ decades, and then seeing numerous 4C's, you should bump out the wheels at least 10mm. 12mm is probably the sweet spot to reduce the offset and get them wheels/tires to have better stance (bumped out).. The higher mm number you go, the more likely camber settings matter, but I'd wager 10mm would not screw up anything.
 

·
Registered
Joined
·
376 Posts
I went with 255/35-19 rears on stock dark teledial wheels with 15mm spacers and no issues. Alignment seems good to me (slight rear toe in and very slight front toe in). I used Firestone Firehawk Indy 500 tires if you want to look up the section width for comparison.
 

·
Registered
2015 Alfa Romeo 4C w package 22C, Coupe Track package, leather upgrade and the forged 18s and 19s.
Joined
·
36 Posts
I just installed exactly what Philster suggested above, a couple weeks ago. No spacers, yet. Made a HUGE difference in the car. Rides and tracks so much better. My factory alignment was pretty bad, a lot of toe out. I set it to 2.5mm toe in. Also installed the Alfa works "race" suspension blocks. I love the car now. I wasn't sure I would keep it before these mods it was so non-confidence inspiring at higher speeds.
Alfa_w_new_tires.jpg
 
  • Like
Reactions: Philster and smc4C
1 - 14 of 14 Posts
Top