Retired Phone Man
Covington, Louisiana
Senior Member
Joined: 03/19/2007
View Profile
 Offline
|
I now have ST175/80D13 tires on my TT. I want to replace them with either ST185/80R13 or ST205/75R14. My concern is the clearance on the inside between the tire and the spring mounts. I now have a little over 1" and with the ST205/75R14 I would have 1/2". Would this be too close.
My TT GAWR per wheel is 1000lbs. The tire ratings are:
ST175/80D13 - 1360
ST185/80R13 - 1480
ST205/75R14 - 1760
I am thinking the ST185/80R13 would give enough added cushion, and the ST205/75R14 may be overkill and would it be worth the risk with the tighter clearance. Any and all thoughts are appreciated.
Thanks,
Jim
2007 Toyota Tundra SR5 Double Cab with 5.7L V8 and Tow Package.
2007 Gulf Stream Ameri-Lite 21MB
Peaches - Lhasa Apso/Mut Mix
|
JIMNLIN
Big Cabin, OK
Senior Member
Joined: 09/14/2003
View Profile
|
my LT215/85-16 E have a 1/2" clearence on the inside (tire to trailer frame) and have no tire rub issues on hard turns. Those 175/80-13 series tires are a very narrow tire sectional width compared to a 205/75-14 tire so. Chesck a tire manufactors web for those two tires sectional measurments.
JIM
'03 2500 Dodge/Cummins HO 3.73 6 speed manual Jacobs
'97 Park Avanue 28' with two slides
|
Retired Phone Man
Covington, Louisiana
Senior Member
Joined: 03/19/2007
View Profile
Offline
|
I measured from the center of my current tires and it was 4 1/2" to the frame, and the tires should be about 6.9" wide which gives me 1" clearance. The ST205 show 8" wide so that would leave only 1/2" clearance.
|
Fisherman
Angus, Ontario, Canada
Senior Member
Joined: 09/28/2002
View Profile
Offline
|
Tires rotate, move up and down but not sideways (other than the flex) when making sharp turns and that's only on the ground, not at the springs.
|
NHguy
NH
Senior Member
Joined: 04/01/2006
View Profile
Offline
|
You will have lots of inside clearance. There will be .4" added to each side of the tires widths. But check overhead clearance and tandem axle clearance. Do you have 2 axles? Your diameter will change from 24" OD to 26.1" OD. This means your tire gets 2.1" taller overall and since half of the diameter change goes to the radius, it's 1.05" taller at the top, that is, closer to the fender or vehicle. So make sure it won't rub overhead in bumps etc.
With tandem axles you have to have at least 1" of clearance between tires. And because you are changing the diameter of 2 tires they will get 2.1" closer together if used in tandem.
Here's where it comes from
Diameter = (Width X Height X 2 / 25.4) + Wheel Diameter
Example 205mm Width X .75 Aspect Ratio X 2 / 25.4 Conversion Factor Between Inches and Millimeters + Wheel Diameter = 26.1" OD
This is based on good old fashioned geometry as used in the tire business.
Hope I helped.
05 F150 FX4 Supercrew, 5.4, 3.73 LS, Jordan Ultima 2020 Brake Controller,
04 TrailCruiser 30QBSS, XM Cradle, Battery Disconnect
Dual Cam HP, Ultra Fab Power Tongue Jack, Bal Lockarm Stabilizers
|
|
|
dclark1946
Richardson,TX,USA
Senior Member
Joined: 10/05/2003
View Profile
Offline
|
I made a tire diameter of only 0.5 inches and had problems with vertical clearance with rub marks on the fender liner. I was able to make use of the spring hanger optional location points to gain an extra 1 inch clearance.
Dick
Dick & Karen (converted tent campers)
Richardson,TX
2007 KZ Spree 240RBS
03 Tahoe/04 F250 PSD
|
Retired Phone Man
Covington, Louisiana
Senior Member
Joined: 03/19/2007
View Profile
Offline
|
I compared specs on the tires and I have plenty of clearance all around. My only concern was the 1/2" on the inside. One tire dealer stated you should have 1" min clearance but I thought I would ask the experts on this forum.
My definition of Expert: Person you call in at the last minuet to share the blame.
Thanks for all the input.
Jim
|
brohloff
Eastern MN, USA
Full Member
Joined: 03/30/2004
View Profile
|
Think I'd want a little more than 1/2" but if the potential rub point is a flat, not sharp like a shock mount might be, you might be able to get by with an occasional "bounce" rub.
Another route is if have some extra clearance on the outside is to replace your rims with one's that have an additional offset from the one's you have. Many rims have "0" offset (the hub mounting surface is exactly in the center of the wheel edges) and a -6 mm or -12 mm offset (both std offsets) would move the tire edge 1/4 or 1/2" respectively out from axle hub.
Talk with a tire dealer and they will be able to help if there is outward room to shift the tire.
'05 3500 CTD SB SRW 4x4
'07 Tacoma 4x4 daily driver
'05 Nash 22H, Equalizer, Brakesmart
|
