BDS 2.5” Coilover Trailboss/AT4

[TXguy]

I’m glad to hear the BDS Fox coilovers are worth the money, because mine are on order. I did go a little different route than the BDS kit. I ordered the 4” Zone kit with the skid plate and the Fox rear shocks. I spoke with Zone about the kit. The engineers for BDS and Zone are the same engineers. The kits are the same except for the front cross member (square vs curved) and the BDS has one extra skid plate. Oh I almost forgot, I was also told the BDS has more logos to show off. The Zone technical person gave me the part numbers to order the BDS Fox coilovers and brackets, same kit so they fit. I did learn the BDS coilovers are not to the same ride spec as the standard Fox coilovers. The engineer told me they are designed so they are not as aggressive and have a softer ride than the standard Fox coilovers.  For the price difference I was able to order the Zone upper control arms ($500) and still save a few hundred dollars. However, I will not get the no questions asked BDS warranty only the Zone warranty. Which I understand Zone fully stands behind their lifts. The only issue right now is long lead times due to getting in parts at both Zone and BDS. I can’t wait to get everything installed. 

[2nazt]

Some websites say you can not use the factory 18” TB wheels with this lift. Is that true? Has anyone tried or has everyone upgraded there Rims and Tires. Do you need less offset to work with this kit?  Thank you in advance. 

[lapoolboy]

The wheel and tire specs are laid out very clearly in both the BDS and Zone installation instructions.  They are readily available on their websites.

[2nazt]

I did confirm with BDS as I found multiple sites with their kit for sale not list you needed different wheels for it to work. That is why I asked. Thanks 

[lapoolboy]

47 minutes ago, 2nazt said:

I did confirm with BDS as I found multiple sites with their kit for sale not list you needed different wheels for it to work. That is why I asked. Thanks 

I'd trust BDS before a third-party reseller.

[Flatblack83]

I changed mine from the icon stage one to the stage 4, giant difference than before. Rides really nice at 3-3.5 inches up front. The 2.5 coilovers with the 2.5 rear shocks makes a big difference..!!   I even thought of the 4 inch zone for the cross members, that would fix the cv and lower control arm angles.

 

So the bds kit with coilovers is probably the best way to go.

[Supercup]

On 10/4/2020 at 6:45 PM, 2nazt said:

Some websites say you can not use the factory 18” TB wheels with this lift. Is that true? Has anyone tried or has everyone upgraded there Rims and Tires. Do you need less offset to work with this kit?  Thank you in advance. 

 

Stock 18" OEM wheels have 26MM offset- which is about 5.50" back spacing on a 9" wheel - you need 4.5" backspacing on wheels to clear the tie rod.  That is about <12> MM - I had Method 18x9 with 18mm offset (5.25" of back spacing) and we thought it would work - it did not clear tie rod - had to add 1.25" of spacer and wheel lug extensions to make it work and it just clears.  Not ideal, but works for now - plan to either get 20" or <12> mm 18 inch soon so I can clear without spacers and lug extensions and add larger tires.

 

With 20" wheel you don't have same issue as the tie rod will clear - albeit it is inside the wheel radius. 

Edited October 8, 2020 by Supercup

[iammrrush]

On 10/8/2020 at 11:28 AM, Supercup said:

 

Stock 18" OEM wheels have 26MM offset- which is about 5.50" back spacing on a 9" wheel - you need 4.5" backspacing on wheels to clear the tie rod.  That is about <12> MM - I had Method 18x9 with 18mm offset (5.25" of back spacing) and we thought it would work - it did not clear tie rod - had to add 1.25" of spacer and wheel lug extensions to make it work and it just clears.  Not ideal, but works for now - plan to either get 20" or <12> mm 18 inch soon so I can clear without spacers and lug extensions and add larger tires.

 

With 20" wheel you don't have same issue as the tie rod will clear - albeit it is inside the wheel radius. 

Any update to this? There is no guidance on the BDS instructions regarding 35" tires with 18" wheels. Is that restriction related to these tie rods?  Just running a negative offset wheel (-13 for 9mmW it seems) will allow for the tie rod to clear? And run the larger tires?

 

Thanks

[Supercup]

3 hours ago, iammrrush said:

Any update to this? There is no guidance on the BDS instructions regarding 35" tires with 18" wheels. Is that restriction related to these tie rods?  Just running a negative offset wheel (-13 for 9mmW it seems) will allow for the tie rod to clear? And run the larger tires?

 

Thanks

-12 mm Method 9"x18" clears the tie rod (4.5" backspacing)- question then is will you be able to fit 35" tires - with that offset the wheel is pushed further out.  since the 35" is 12.5" wide, same as the 33" they say will fit with this set up, it would seem that the issues on the 35" will be, with it pushed out another 1", versus a 20" will it require "more" trimming or just not fit at all.  I can say for certain there is no "tire width" issue on the inside.  From the inside of the 275/65/18 I have there is about 4" of inboard clearance (measured with tape).  The tie rod also would not interfere with a 2" wider tire.  So issue to resolve is the taller height and what is the impact?  When I got mine put on they suggested that 33" or 34" would be the way to go with 18's, but never said 35" would not work.

 

The guidance states 35" will fit with 20" with 5.5" - 6.25" pf back spacing - which moves the wheel back in and places the tie rod, within the wheel radius.  Can't draw any conclusions - will probably have to be trial and error at the tire shop! 

 

Here are a few photos of inside clearance with my current set up with the 275/65/18's - which are 32.3" diameter and 11.0" section width wide.  Currently at full lock in reverese the just barely rub on the inside.  So no matter what, with this set up larger tires are going to need trimming - bigger you go, the more it will require.

 

Looks to me like the first pinch point is the gap between the "front" of the tire and the lower corner of the front fender - that has about a 2" gap - so if you went up 4" in diameter (31" to 35") you should have 2" of growth on either side (right?).   That would put the 35" right up against that front fender.  The rear fender gap is 3".      

 

I would say if you want to go with 35" tires the 4" kit (which is 6" overall) may be the safer starting point.   If I do more tire work, I will post up, but not planning to go bigger, unless I get new wheels. 

 

Photos show

1. tie rod clearance

2. Top clearance steering knucle 

3. Top clearnace

4. Front fender clearance - two finger - inside out

5. Front fender clearance - inside out

6. Rear fender clearance - outside in

7. Front fender clearance - inside out 

 

  

[iammrrush]

Great response, thanks. How far out your fender is the tire sticking out? I may switch to 20" wheels if it will keep the tires further in.

Sent from my Pixel 4 XL using Tapatalk

[Supercup]

Here are a few more photos of tire clearance - with stock 275/65/18 Duratrac's on Method 18 x 9 wheels with 18mm offset - 2.5" BDS Coilover lift on 2020 AT4.

 

first one - front tire - front clearance - straight wheel - looking inside out.

Second one - front clearance - straight wheel - back of tire

third - front clearance - straight sheel - front of tire

fourth - front clearance - 2/3rd turn of wheel - front of tire

fifth - same as fourth - view further away 

 

 

[Supercup]

A few more 

 

first - front of tire 2/3 turn

second - front of tire full lock

third - front of tire full lock

fourth - front of tire full lock - just barely misses wheel liner 

 

Edited November 11, 2020 by Supercup

[Supercup]

Last Few 

 

first one - front 2/3 turn

second one - rear of tire full lock

last one - front of tire - 2/3 lock - closest pinch point - will rub over - larger tires would need this area trimmed. 

Edited November 11, 2020 by Supercup

[iammrrush]

Hello everybody,

  After a two month plus backorder, I was able to get my 2.5" (4" total) BDS lift kit on my AT4. I kept the 18" wheels (-12 offset on 9 in wide) and put on 35x12.5" Nitto Ridge Grapplers. I trimmed a small amount on the front lining due to rubbing at one angle. The bigger issue was in the back that required some trimming of the bracket. Even then, there was a tiny rub that probably would have gone away after a few miles on the road. A couple small hits with the hammer on the bracket allowed the tire to clear without touching. The ridge grapplers are almost a true 35" (actual 34.76") and I think if I had gone with a tire that was 34.5" there wouldn't have been any rubbing on the bracket. You'd still have to trim the mud flap I imagine. If you are concerned and want to give yourself room for error, shoot for ~34.3". The front may be affected more with a stock front bumper, as I have a replacement. The guide on the internet is fairly accurate, but I did not take the bracket off. Just heat and cut.

 

https://wheelsasap.com/gmc-at4-oversized-tire-trimming-guide/

 

I didn't take pictures of the bracket/flap rub on the back, unfortunately. Hope this helps.

 

JR

[Supercup]

Turned out great!  Thx for the update on the wheels and tire sizing - very helpful.  Next step for me to swap out my current methods for one's with -12mm offset, like you got - gives me a great guide for tire size - probably go with 33/12/5/18 BFG's.   

 

How do you like the ride and performance now that it is installed?