Tamiya Suspension Mount Ultimate setting Guide and charts

The Tamiya suspension mounts are a powerful tuning option to help you refine the way in which your car will handle on the track. They are also compatible with many different Tamiya chassis. So if you are a Tamiya racer they are a sound investment as you will be able to usually use them on new cars as you upgrade.

The following  guide will help you understand the difference between all of the various Tamiya suspension mounts, and will provide information on the different handling scenarios that you can achieve by adjusting them, and a whole host of other bits of info.

Different Mount types available.

So what is a suspension Mount? Well these hold the hinge-pins that the suspension arms move on. These were introduced with the The TBEvo3 in 2002. Even now many of the new suspension mounts types are compatible with many older Tamiya chassis (A compatibility chart is included later in this guide). However over this time there have been a few different types, so let's take a closer look.
Alpha mounts
Alpha mounts were the first type of suspension mounts. They were made in a few different colours to match the chassis they were included with o you will find Silver (TB EVO III), Red (TB Evo Surikarn edition) and the classic Blue (TB Evo IV/ TRF415). These are not sold anymore, and they were replaced with the much more versatile 'Uno' mounts.
Uno Mounts
With the TRF415 the mounts were revised to the 'Uno' versions. The mounting positions to the chassis are the same as the 'Alpha' mounts however they have a 1 marked on them in front of the width letter (Hence Uno). This 1 is significant as it denotes that the block is 1mm lower than the 'Alpha' mounts.
Uno V2 feature slightly tweaked geometry to the V1 mounts
The Uno V2 mounts are the ones that you can easily order today. Around the TRF416 era the Uno mounts were revised. The font changed and the geometry was tweaked slightly to work with the shorter hinge-pins on the TRF416 (And all subsequent Tamiya Chassis). So be careful if you mix and match the Uno and Uno V2 blocks. As the earlier ones are not the same width (A V1 E block is slightly wider than a V2 E block).
The Bridge mounts are old and not worth seeking out
The Bridge mounts are very uncommon, and there are only two widths available. these were made to clear the belts in some chassis. The Uno V2 mounts are able to perform the same function by flipping them over and adding a 3mm shim under each side to ensure they can clear the belt.
05 Mounts
05 Mounts. These are 0.5mm lower than the Uno V2 style mounts to provide a lower roll centre.They are not available in as many sizes, and as a rule are intended to be used at the front of the car

The latest mounts are the Adjustable mounts. As the name suggests these mounts allow you to tune the ride height and the width by fitting a range of different plastic bushings that come included. (More detailed info on the mounts here) These dramatically reduce the amount of money you now need to spend for a range of tuning options. They also come in a split mount version, talking of which...

Split mounts

Split blocks are used on the FR and RF positions on the chassis. They obviously help avoid the belt. However they are primarily used to allow chassis to flex more, so can be a useful tuning aid.
V1 Split Mounts
The V1 split mounts were introduced on the TRF417.  They have the same Geometry as the Uno V2 mounts, so 1A solid and 1A split are the same. The mounting holes are symmetrical so depending on how you attach them to the chassis you will usually find that they offer you two different settings. For example the 1A mounts when attached so that the left one is on the right of the chassis and vice versa provides you with a 1XA setting.
V2 Split Mounts also available in 05 and adjustable varieties
The TRF419 introduced a new design for the split mounts. These have the same geometry settings as the Uno v2 blocks and the V1 Split blocks however they were re-designed to be really solid (although I never had an issue with the other blocks),  there new shape includes a chassis locating pin.

They are not compatible with chassis that have mounting holes to accept the V1 split mounts, and they also are not reversible.

Where are they positioned to the chassis?

There are 4 positions that you fit the suspension mounts on your Tamiya chassis. Two in the front and two in the rear.
Example mount positions on a TRF419 chassis
They are referred to as FF (Front Front), FR (Front Rear), RF (Rear Front) and RR (Rear Rear). I will refer to the positions as these from now on.

What do the markings mean?

The markings show two important parts of information. The letter denotes the width, and a number illustrates a height. Take a look a the mounts in the picture below.
There is 1.5mm difference between the highest and lowest hinge-pin position for these blocks
The adjustable blocks (ADJ) on their lowest setting provide the lowest position, followed by the 05 Mounts (05D etc), these are 0.5mm lower than the Uno Mounts (1D etc) which are in turn 1mm lower than the Alpha mounts that do not have a number in front of them.

The letters refer to the width of the mount. XD is the most narrow mount position and G is the widest mount. The guide below will show you the differences.

The chart above shows the entire range of suspension mounts from the theoretical lowest narrowest 4.0mm  XD width, and the highest widest 5.75mm and G width

What happens when I change the Mount width?

Now we know that the mounts are all different widths, you can change them on your chassis to change two basic types of chassis setting.
  1. Toe angle 
  2. Track width

How do I change the toe angle?

Well each of the mounts gives the suspension hinge-pin a 0.5° difference to the one that is supersedes. You can use this to change your 'Front Arm sweep' and 'Stable Rear toe in'

Front Arm Sweep 

Usually at the front of the car both the FF (Front Front) and FR (Front Rear) suspension mounts will be the same width. If you replace the FR (Front Rear) block with a narrower one you will add front arm sweep to your car. Normally you would just run 0.5 degree sweep, and you will never want more than -1 degree of front arm sweep.

Front arm sweep makes your suspension bind as the front hinge pin is at an angle. This makes the front end stiffer. This is because as the weight moves forward the hinge pin is angled into the opposite direction of the corner. This delays weight transfer going forward but as the suspension binds it applies more pressure on the tyre, creating more traction and increasing your mid to exit corner steering.

  • More arm sweep = less initial turning but more in the corner around the apex.
  • Less arm sweep = More initial turning, less at the corner apex

Rear Stability Toe In

At the rear of your chassis you will want to have the RF (Rear Front) mount more narrow than the RR (Rear Rear) block to provide some rear stability toe in.

As a rule of thumb you will want between 2-3° of rear stability toe, the larger the amount of Rear Toe in the more stable the car will be, although it will slow the car down on the straights as there is more drag. (I run 2.0 or 2.5° in blinky, and 2.5 or 3.0° in Boost / Mod).
  • More Rear Toe in = More stable but more drag
  • Less Rear Toe in = Less stable but less drag

As you can see in the above charts you can set the rear toe in to 3 degrees with a combination of different mounts such as : RF: XD & RR:B, or RF:X & RR:F. The difference is that they are at different widths.

Track Width

Changing the track width is another tuning option. Each mount has 0.75mm difference in width the mount that precedes it.

As a point of reference, the UnoV2 blocks 1A = 43mm for the width, so E.G 1C =44.5mm.
*These widths are relative to each other, however Alpha and Uno V1 blocks are wider than the modern equivalent.
As the chart above shows you are able to make a massive 8.25mm difference in width from the narrowest suspension mount to the widest one. This can make a large impact on the handling.
  • Narrow track width more grip.
  • Wider track width less grip.
** NOTE** Remember that the Alpha, Bridge and Uno V1 mounts are wider than the current Uno V2 etc blocks that we can buy today. So it is best to pair the older ones and newer ones together or at least take this into consideration.

Suspension Mount Height adjustments

So we have covered the tuning options that the different widths give us, now let's look at the wealth of tuning options that we have by changing the height of the blocks.

For the new adjustable blocks you can change the height by replacing the bushings.
Tamiya mount spacers are available, or you can use shims.
For the older mounts, or if you want to go even higher than 5.5mm, You can change the height of the blocks by either by using the Tamiya suspension mount spacers, or swapping out to one of the older 'Alpha' mounts.

The main things to tune with the height are:
  1. Roll centre
  2. Front Kick-up / Anti-Dive
  3. Front Pro-Dive
  4. Rear Anti-Squat
  5. Rear Pro-Squat
Remember, Tyres, shocks, springs are always your first call when tuning a chassis, especially from the stock settings. 

1. Roll centre

You can change the roll centre measurements by raising or lowering the hinge-pins with the suspension mounts. The lower the arms the lower the roll centre, and as you would expect, raising the arms will raise the roll centre.
Add shims to raise the roll centre, remove to lower it.
The Roll centre is the point where the chassis rolls. It is usual to have different front and real roll centres. The roll axis is the line along the chassis between the front and rear roll centre. The amount that the chassis rolls in the corner depends on the its relation of the roll axis to the centre of gravity.

The impact of roll centre adjustments are instant as it effects the cars predisposition to start to roll in a corner, other suspension elements such as shocks and springs only start to work once a car rolls.
  • Lower Roll centre will give you more grip as you will put more pressure on the tyre as you corner. 
  • Higher Roll centre will give you less grip but make the car more responsive. 
Tip - Adding and removing shims from the lower blocks have a more drastic effect that changing the shims on the the upper bulkhead. You should always adjust them first before shimming the lower blocks. Also due to the way in which the roll centre's geometry works, For the bulkhead shims, more = lower roll centre, less = higher roll centre. 

2. Front Kick-up / Pro-Dive

Kick-up refers to the hinge pin angle relative to the chassis. As a rule on most onroad RC cars it will be parallel to the chassis and will have no kick-up.

However if you raise the front front suspension mount (FF) or lower the front rear suspension mount (FR) this will give you kick-up.

Front Kick-up softens the front suspension and it increases the amount that the front of the car will dip when you brake, transferring the weight forward more easily.  It also adds more caster to the front hubs, which means that you will have more camber gain as you turn around the corner.

  • More Front Kick-up = More initial steering, less steering around the rest of the corner.
  • Less Front kick-up = Less initial steering, more steering around the rest of the corner.

3. Front Anti-Dive

If you lower the front front suspension mount (FF) or raise the rear front suspension mount (FR) this will give you Front Anti-Dive.

Anti dive will allow you to run a slightly softer front spring without the front of the car diving too much under braking. This reduces the amount of weight that will be transferred to the front of the car when off the throttle or braking.It also reduces caster, which gives you less camber as you take the corner, reducing the amount of steering you have through the corner. It is not a very common setting for most racers.
  • More Anti Dive= Less initial corner steering, more steering around the rest of the corner from the apex.
  • Less / no front Anti Dive = More initial corner steering and less steering around the rest of the corner. 

4. Rear Anti-Squat

Anti-Squat refers to the hinge pin angle relative to the chassis at the rear of the chassis. As a rule on most touring cars it will be parallel to the chassis and will have no anti-squat. However if you raise the front rear suspension mount (RF) or lower the Rear Rear suspension Mount (RR) this will give you anti-squat.

Anti-squat stiffens the rear of the car, so it reduces the amount that weight transfers to the rear of the car on acceleration. This will give you less traction on the rear tyres but you will gain more steering. As a rule of thumb most drivers always want more rear traction, but sometimes when the grip is high, especially now with the black carpet a car can be very lazy, so anti-squat is something that can help, even if you just add a small amount of shims (0.3mm) etc. Also this setting can help along with front kick-up if the track is bumpy.
  • More Rear Anti-Squat = Less traction at the rear, car will have more steering response.
  • Less Rear Anti-Squat = More traction at the rear, car will have less steering response.

5. Rear Pro-Squat

Rear Pro-Squat refers to the hinge pin angle relative to the chassis at the rear of the chassis. As a rule on most touring cars it will be parallel to the chassis and will have no rear Pro-Squat. However if you lower the front rear suspension mount (RF) or raise the Rear Rear suspension Mount (RR) this will give you rear Pro-Squat.

Rear Pro-Squat softens the rear of the car so this allows more weight to transfer to that end of the chassis when accelerating. This causes the car to have more rear traction. As the weight has moved to the rear this takes away some of the front traction so reduces the responsiveness of the car as it steers, giving you less initial steering. This setting is not used very often, you are better off to change your rear springs or the rear shock mounts, but it can be effective on some smooth circuits.

  • More rear Pro-Squat = More rear traction, less steering response
  • Less rear Pro-Squat = Less rear traction, more steering response

Chassis compatibility

Ok, so you have a Tamiya chassis. Here is a chart that shows you which type of Mounts you can fit to your chassis.

Part Numbers

Here are the part numbers for the various suspension mounts and the correct mount spacers.

Phew! Hopefully that covers most things related to suspension mounts. Remember most of these setting are for advanced drivers. Initially just the rear Toe Stability Toe is the most important thing to change to help make your car easier to drive.
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Post a Comment

  1. Awesome. Have been looking for this!

  2. This is brilliant. I've been struggling to understand which I needed for my TA07, and this article gave me all the information I've been struggling to find and understand.

    Thank you!!

  3. This a great tool you have put up here. I have a question though. Typically I think of negative ad toe out and positive toe in. The chart seems opposite. I's that correct?

  4. Toe in is negative and Toe out is positive. (It is about the leading edge of the wheels and where they sit relative to the rear).

  5. Great artikel juist a quick question, does it matter wich suspention mount is used forward and wich one in the rear?
    I am racing the TA07pro and want to get the alu adjustable mounts front and rear but.....there are types A,E and XB(partnumbers 54881,54882 and 54880) so what is the differance between the mounts??
    And if i get type A do i need the alu adjustable separate mount A type as well or can you mix the types??

    Hope you can help me on this one.
    Regards ilja

  6. I see that the TRF414 is listed, will these upgrades also fit a TA04?

  7. Great info! Thanks!! I only found lacking info on the XV01's compatibility. Any chance pointing me towards this info, please? Thanks!!

  8. Hi,
    Thanks a lot for this very detailed article.
    As a beginner I have still difficulties to grasp/understand some concepts and, for me, certain aspects developed in this article feels a bit complex.
    Do you think that an article showing a progression in the difficulty such as basic but mandatory aspects to configure followed by another section for advanced configuration and even an expert tuning section would be worth considering?
    Thanks a lot for sharing your knowledge



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