Stiffest 4-Bolt Booster?

[Sponge]

Hey, I was just wondering about this and wanted to see if there were any riders that know much about the design of boosters.. in that I mean if it's possible to predict/theorize if Booster A is stiffer than Booster B? I ask this because I really enjoy having the stiffest brake possible, with absolutely minimal flex. It just feels better at the lever and in general for me personally.

Moreover, I'm building up a certain mod slowly, which I know has major issues with brake mounts cracking looking at its track record on the forums over the years... so I also want to reduce any chance of that as well.

I'm mainly comparing 3 boosters: Heatsink, Trialtech 4-bolt, and Tensile

Over the years I've picked up that there are a lot of lighter parts that are stronger/stiffer than heavier parts, so wondered about boosters. I realise that the Tensile and Heatsink boosters are comparatively heavy at almost 200g each. Whilst the T-tech is around 1/3 or so of that weight.

I'm just looking for a completely objective opinion if it's possible to see how optimized the booster shape is for stiffness. In short, I'd just like to know which one offers the stiffest performance and only that. I don't mind about weight at all as it's only 100g extra for the heaviest. Whilst I'd like to support a rider-owned brand like Trialtech (of which I'm going to run several other components) if another brand's (cheaper) booster is going to give me the tiniest percentage more stiffness then I'll go for one of those. I realise the T-tech probably has the best stiffness:weight ratio of the three but I'm totally discounting weight in this case.

Any thoughts?

Thanks!

[Greetings]

Out of those three I've only had first hand experience with the HSB booster. It was very stiff.

How about a TNN brake booster system and a 4-bolt booster on top of that?

[Matt Burrows]

Out of those three I've only had first hand experience with the HSB booster. It was very stiff.

Agreed! I run one on my Adamant frame, which has a thick CNC booster built in. But even so the difference in brake stiffness and the improvement in brake performance was very noticeable.

[Sponge]

Haha! That's going to be serious overkill! I'm not going quite that far, but thanks for the suggestion though!

The most I'm willing to spend is £35, which is what the new Ttech one costs...

The Tensile and HS seem to have a thicker profile overall, especially the Tensile having a really straightforward simple design. In this case, is it fair to use overall booster thickness as one measure of stiffness? .. But taking into account the rest of the design of the booster. I don't think Trialtech would release a flimsy flexy 4-bolt booster after all this time, so I'm pretty curious about how a thinner well-designed booster fares against the brutishly thick and simple ones?

I understand that almost no-one'll have used all 3 to give a fair comparison from experience, but I'm just hoping to find an answer through objective analysis, with no bias of what brand or weight. The booster is just one part I personally just look for only its main function: to provide as much reinforcement/stiffness as possible and nothing else. I figure there are other more effective areas to save weight on, not that it really matters for this particular mod I'm building up as it's a bit of a beat 'em up throw around bike to relearn some techniques and learn new ones. I'll worry more about weight saving when my riding ability reaches a point where it can really benefit from it.

[AdamR28]

Tensile or HS are stiffest out of those three. Such a stiff booster isn't really required though, IMO. You can easily double the weight and only add 20% stiffness, for example.

Out of the three I would use the Trialtech.

[Mikee]

Heatsink and tensile are both brilliant from my experience. But for some reason ( I think I probably read it on here ) I have it in my mind that there were tyre clearance issue with the heatsink booster on mod bikes. I'm sure someone will correct me if i'm wrong.

[Shaun H]

To generalise, the deeper and taller a booster's cross section is, the stiffer it will be. Stiffness is a function of a materials' modulus of elasticity E, and the geometry's second moment of area I. Since boosters require stiffness driven design, out of the two popular 6061 and 7075 alloys, 6061 tends to be used since there isn't a large difference in their moduli (6061 about 69 and 7075 about 72) and 6061 is a bit lighter and is cheaper.

I sort of agree with Adam that you don't necessarily want the extra stiffness offered by heavier boosters since increasing the cross section of a booster (and increasing weight) won't return a similar increase in stiffness for some dimensions. Increasing the width of a booster's cross-section is the most efficient way of increasing stiffness however there's little scope to do this when working around rims, tyres, brakes etc. Failing that increasing the booster depth increases stiffness but this also considerably increases cost, since a larger amount of material has to be machined away in the webbing (pockets), hence, some boosters sticking with a thinner shape and simple, minimal machine operation profiles that (should) make for a cheaper product.

EDIT: In answer to your question, the Tensile booster is the stiffest one I have ever used, however I found it couldn't be run with unworn brake pads.

Edited November 24, 2010 by Shaun H

[Mikee]

In answer to your question, the Tensile booster is the stiffest one I have ever used, however I found it couldn't be run with unworn brake pads.

I never had the pad problem. Did you use the bigger spacers it comes with? As I tried it with the smaller 'standard' size spacers and the pads wouldn't fit under the booster properly because it was too wide.

[Sponge]

Thanks to everyone who replied, especially Shaun. That was the kind of answer I was looking for!

As soon as I first glanced at the depth part I immediately had thoughts that a 12mm thick booster like the old Echo Control or Heatsink ones would be stiffest. The Tensile is 10mm thick, though seems an overall larger booster? It's interesting that you say the Tensile is stiffest of them all. Guess that works out pretty well as they're the cheapest too!

///

Re: the spacers on Tensiles, were you referring to these fat ones with the lines circling the length of them? Are they actually a fair bit longer than the normal thinner spacers you see on other boosters?

[Mikee]

Re: the spacers on Tensiles, were you referring to these fat ones with the lines circling the length of them? Are they actually a fair bit longer than the normal thinner spacers you see on other boosters?

Yes they are longer. You see on the inside of tensile booster the sides are straight near the mount holes... on other boosters they are cut out abit to clear the pads. So the longer spacers are needed otherwise the pads will hit the side of the booster.

Edited November 24, 2010 by Mikee

[Sponge]

Interesting! By the way, did your Tensile booster come with 50mm long bolts instead of the standard 45mm ones? I have one sat here to put on my brother's new stock, but when experimenting it seemed the bolts were a tad long and bottomed out in the frame before any tightness could be reached.

I wasn't using any washers since mine came without any (2nd hand), are you using washers on the topsides and undersides of the booster by chance?

[Mikee]

Interesting! By the way, did your Tensile booster come with 50mm long bolts instead of the standard 45mm ones? I have one sat here to put on my brother's new stock, but when experimenting it seemed the bolts were a tad long and bottomed out in the frame before any tightness could be reached.

I wasn't using any washers since mine came without any (2nd hand), are you using washers on the topsides and undersides of the booster by chance?

The bolts are a tad longer I believe. I got mine new so I have exactly what is in that picture. Proper bolts and spacers.

[Shaun H]

Thanks to everyone who replied, especially Shaun. That was the kind of answer I was looking for!

As soon as I first glanced at the depth part I immediately had thoughts that a 12mm thick booster like the old Echo Control or Heatsink ones would be stiffest. The Tensile is 10mm thick, though seems an overall larger booster? It's interesting that you say the Tensile is stiffest of them all. Guess that works out pretty well as they're the cheapest too!

If you look at the equations for second moment of area for a beam you'll find the general formula:

So looking at a booster, making it taller has a much bigger effect of making it deeper although it is important to point out that is theoretically!

Edited November 24, 2010 by Shaun H

[dirt jumper jake]

The only booster that ive heard of to stop a 05 python cracking, is an oldschool echo one similar to the urban. i know as i had one on mine and so did my mate...