I am measuring from my rear axle drum face to the inside of the rear fender and to the body to determine my wheel offsets and tire width. Naturally the goal is to fit the widest tire possible. What is the recommended clearance between the tire and inner fender lip and tire to the body. Thanks in advance for the replies.
Think it would depend on the type of suspension and tire. Some move around, some don't. One thing to keep in mind, clearances with the tire going flat. Don't want to tear things up.
Its either play it safe or trial and error. Your choice. dont forget clearance i affected by body roll or lifting a wheel With me it was trial and error with wheel spacers to get the clearance the got wheels to the desired back spacing
An additional consideration when picking a tire width is in how difficult it will be to remove or install when the car is on a jack. Drum to drum width can be an important consideration. Height and shape of the wheel well opening must also be considered. Sometimes a special width rear end must be built as well as custom offset wheels in order to get what you want. Do a lot of measuring and calculate what you want for your car. I went through many combos on my 51 before I got to my current configuration, OEM wheels and OEM bias plies, flatter leafs, lowering blocks, and a custom width Curie 9” rear. With a hot rod or kustom, change over time is completely standard if you keep the car for a long time.
I like to remove a tire and use a sturdy jack stand under the axle or spring perch so the suspension is under normal load. Then clamp a stick to the hub face (you can use lugnuts to do this) and trim the stick from hub center to the tip to match the radius of your tire choice. Then cut a cardboard template to the width and shape of the tire cross-section. Mark the center of the template and the hub face 90* off the hub on the stick tip (this should be the inner edge of the stick if it is straight). Then attach the template to the end of the stick and swing the jig around the entire sweep in the fender to check the spacing. (Keep in mind that the suspension will compress with road bumps and load so mentally estimate the template stabbing farther up into the fender.) With a bit of measuring you should be able to note any extra space to the inside or outside as well as lack of space. It won't take long to figure out how much tire width you can add (or not) and how much offset/backspace you need to maximize how much tire size you can stuff in there.
I remember finding just the right wheel and tire combination for clearance. It worked up until the time I went around the first corner.
A simple question. Good replies with additional considerations and the need for more information. If the OP provides the type of car, rear suspension, driveline and whether the car is lowered, I believe there are many on here that have the experience to provide the range of parameters from 'good to go' to 'living on the edge'. Now to hi-jack the thread. I was about to post the same question for the rear tires on my '57 Chevy PU, parallel leafs, lowered 3".
An inch is usually pretty safe. Less than that....is when it gets iffy. Also it's pretty common to have plenty of clearance at ride height, but the fender curves in above the tire, and this is where you usually have problems, when driving through a DIP in the road. So....what car it is, and how high it sits, plays into it, and you didn't tell us.
Without a panhard bar or Watts link, you'll want lots. I smell rubber when I throw mine into a hard corner
Hello, Everyone has a good suggestion on clearance. One inch does sound safe. But, remember, the width of the tire under any fender and what happens when the car is lowered. Not lowered with cut coils or shorter springs, but when other people get in the coupe/sedan. If that is a normal thing, the extra weight will lower your car, more so than what you set the height. Back in the teenage days, we selected tires and rims to stay as normal as possible. Most sedans had the same tire sizes all around. For safety sake and for ease of changing flat tires or damaged tires. It helped if you were a long way from home and all tires were the same size for any exchanges. But, when we got the right size tire and rim installed, it looked good. But, that was with a normal height sedan. We forgot or it slipped our minds as to the tires, clearance and ride height. We were stopped many times by the CHP or local police to check illegal lowering clearances. With just me or with a date, the Impala was normal height with the selected tires/rims. It rode well and looked perfect proportion to the body style. But, if there were 4 teenage boys in the Impala, the overall height was so much lower and that was a cause for the CHP or local police to pull us over. I knew that we would pass when we all got out and the tape measure came out to show the height or lack thereof. The CHP did not know in their rush to judgement on a “lowered” car with teenagers. It was lower than normal, but when the 4 teenagers got out, the Impala or any car goes back up to normal height, empty. We still had to endure the scrutiny of the CHP parameters. Jnaki So, take into account of the tire size and rim width. Put them on the car and see how it clears. Then if the added weight is going to be a regular thing, then modify the suspension or get different size tires. We liked to keep the tires as close to stock as possible due to not wanting to spend time in the speedometer shop getting modifications to run at normal speeds on the speedometer/odometer readings. But, if we did get different size tires, we just knew the rpms versus speeds and knew the mileage readings were off. So, something like at 2500 RPMs, it was going … speed, etc. There is no one correct answer and you will have to decide by manually trying tires/rims and seeing for yourself. But, also take into account the “lowering” factor with added weight. Note: My brother's first 51 Oldsmobile had his try at lowering. A friend was told 2 coils was perfect for cruising. So, my brother had two coils cut. It looked great, but was very low in front. He had a difficult time coming up the driveway entrance without scraping. After a new set of coils, he cut one inch and it stayed that way until he sold it in the fall of 1957. When his friends were in the sedan, it was lower than when it was just sitting in the high school parking area or at a drive-in restaurant parking lot. weight makes it much lower before and after the modifications. YRMV
Also keep in mind that an angled entry ramp like one might see going into a parking lot may cause the rear axle to tilt and the upper part of the rear tire may rub the inner fender well. I stuffed my (non HAMB) car really well. The tires came with raised white letters and we turned those inside. It is literally just the letters on the sidewall that rub as described. LOL. Not too worried about those. It doesn't touch the sidewall otherwise. The tires clear under all other circumstances.
I find on my stuff that if I can stuff my fingers between the wheel arch and the sidewall, it won't rub there. Depending on the shape of the inside of the fender and your ride height, you may need to give a little more clearance. Upper clearance depends on your suspension style and expected travel.
The distance between the inner fender lip and the body determines where to start. I'd allow an inch beteen the body and the back of the tire. How much you allow on the face of the tire will depend on not only your suspension type and sway bar.........but the type of car. A 32 Ford will be different than a 49 Ford. Once you have a dimension for the tire, not the rim..........get an old one at a tire scrapyard and make sure it fits like you want. Also once you have firmed up the tire size, get the rims you are going to use..........then with the tires and rims in place, measure the width of the rear end you will need. Make the rearend 3/8-1/2" shorter than you need on each end. That will allow you to have some "final adjustment room" once its all assembled. Put it together and drive it. If no rub anywhere, space each end out if you want them closer to the fender. Measuring is great, but if you don't want to be worried later on, get the right parts and allow yourself some adjusting to get the best fit up.
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