Brake piston spreaders

Have a look for a co. Called sumart

I have one called “Ultimate piston press tool”  (very generic name!) from Amazon. There seem to be many that do roughly the same thing (sliding wedges with parallel expanding faces) on Amazon.

It does make a job I dislike into a moment of workshop bliss.

too push for just jamming a couple of flat head screw drivers and wiggling them about with wild abandon? Well la di da

I have the Birzman Double ended piston pusher, as I couldn't face the cost of the SRAM tool. I was initallly disappointed, as the plates don't push parrallel, once you start to press against the pistons. What I did find was using a large flat bladed screw driver, you can help the end that pushing in, and the tool works fine. Would I recommend it, over jamming two flate head screw drivers in, defnitely as you'll struggle to damaged the pistons with this tool.

If I was buying again now, I'd be tempted by that Sumart tool or a clone of the sram tool TBH

Flat headed screwdrivers and some old pads to protect the pistons.

I love a tool but I've found a tyre lever works really well to open them up and haven't had the need to get one

Tool needed on a bigger caliper/system though (e.g. a car)

I've an old Stanley flat headed screwdriver that was abused and the head rounded so I filed it smooth. Works a treat.

It’s definitely the “luxury tool” end of tools since I have used the old pads/screwdriver for years. Which works, until the moment the screwdriver slips and the pistons aren’t parallel. Then it’s a pita!

very much nice to have but not essential in the tool box

Occasionally using a tyre lever/screw driver etc can cause the pistons to become crooked and then they will never retract all the way. I had this issue and when I took to LBS to rectify the fact that I could not get the rotor in past the newly installed pads they got the SRAM tool out and went “oh yeah, common issue. This will fix it.” And sure enough it did. I then went and bought the SRAM tool and it makes fitting new pads, pad gap reset, pad advancement process a very simple job. Some SRAM group set components come with a plastic version of the tool that does a similar job but you can’t screw it in so less useful for mis aligned pistons I suspect….

Careful you don't blow the bladder if it's on Shimanos and you've topped up the fluid since the pads were new though.

Has anyone got a link to the clone ones please of sram? I too want one of these as I’m forever chipping my calipers with screwdrivers etc would like a nice tool that does the job quickly and mark free- however the sram one is just not justifiable at all at that price but wouldn’t mind a cloned version or a cheaper branded one that does as good a job

I have a specific Massive ****-Off Screwdriver, it'll never be used to do up a screw but with old pads in it's an absolutely perfect piston spreader, the taper is just unimprovable. I'm all for a "proper tool" but in this case ime this works as well as the SRAM tool but faster and cost me like £3, so by keeping it in the bike tool rack it became The Proper Tool.

https://amzn.eu/d/9M7HPNF

Will probably get one of those. There are a few similar knockoffs. The Sumart looks good, but not sure where to actually buy one here.

A largely unnecessary tool, but it'll come in handy sooner or later. While using a Park Piston Press a few years ago I did manage to snap the pad bolt tab clean off a caliper. One of those "Did I really just do that!" moments. Peak ham fisted dumbass stuff.

I’ve the SRAM tool. Only used a couple of times, really had to crank it to get the pistons back in. Makes you realise that using anything else would have been bordering on the impossible. Also reduces risk of scratching the calipers etc.

The Park one has a tendency to mark/put a ding in the calliper. Hateful thing.

Are the SRAM ones or their clones wide enough to do 4 pot calipers? Problem with them is that as you push back one pair, the pressure squirts the others put so need to be done all at the same time preferably.

I think the Park Tool press is meant to be inserted between the pads to push the pistons back, not contact the caliper body or pistons directly?

Is this the SRAM one people are talking about?

If so, seems like an interesting solution to their design fault (i.e. sticky pistons that easily misalign).

I have one of these - https://uniortools.com/eng/product/1750-2DP-US-disc-brake-piston-spreader - which surprisingly doesn't work that well with my SRAM G2 brakes *sarcasm*. Guess I'll need one of those expensive official ones.

Yes, i’ve used it on Codes. Contacts both pistons on each side maybe 60% of the surface area. Has a hole in it to hold in place using the pad retaining pin

Yep, that’s the SRAM one. That Unior is similar to the Park one which I don’t like.

I tried the Park one with the pads still in and it’s even worse as it doesn’t push the callipers back evenly and also chips the pad material,  so if it’s supposed to be used that way it’s not great at all.

Yep, the Unior and Park ones are supposed to be used with the old pads still in as they are made of steel and will damage pistons.

The issue I have with them is that they don't seem to work so well with SRAM 4-pot brakes because they don't evenly push the pistons back in. Works perfectly with our bikes that have older Shimano 2-pot brakes.

I didn’t know the SRAM tool existed until I read this thread. Looks great in the video but a bit pricy. I’ve ordered an Ali express version for £20. Looks the same hopefully it will do the job well. Must be better than the screwdriver I currently use.

The double wedge system looks like a sensible approach to me, at least over the lever types...

Personally, I now use a C-clamp to *pull* the pistons back in individually. This (a) seems more positive, and (b) allows me to restrain one piston while 'working' the other back and forth to unstick things.

I don't see how the sram one or its copies would work with 4 pot brakes - which are the most difficult to deal with.  And it doesn't actually put pressure on the pistons parallel, which would seem to be what you'd want.

I've got a couple of the lever tools - a park one and something cheap I used to make up an order for free postage.  they're best used with pads in and you have to be careful what you're levering against.

Best results I've had - as others have said, is using an old set of pads and a big screwdriver.  Especially if you twist the screwdriver rather than levering it.  the only tool above that seems to attempt to do the same is the birzmann and Zippy says you have to use screwdriver with that anyway.

Careful you don’t blow the bladder if it’s on Shimanos and you’ve topped up the fluid since the pads were new though.

I only learnt about this recently.

Idiot destructor of Shimano levers.

I’ve got a couple of the lever tools – a park one and something cheap I used to make up an order for free postage.  they’re best used with pads in and you have to be careful what you’re levering against.

I use the Park lever tool… with old pads in… but don’t take my advice (see above).

After years of using screwdrivers, tyre levers and the "not great" Park tool, I've just ordered this Sram tool. Ordered from BikeInn for a reasonable saving; I don't really like using them but better than supporting knock-off stuff imo.

I've always managed fine without the proper tool, but I've rarely regretted buying decent quality, niche tools. So long as it covers more than half of each piston, then it should be fine with 4-piston calipers. We have pretty much the whole Sram range in our house so it'll soon get tested. I'll report back!

Do you not pay customs on the bikeinn site to the uk? I’m tempted treat myself too for xmas as it’s a tool I use a lot as I’m forever removing installing both wheels so inevitably everything goes out of whack over a few weeks and give them a good lining up again

I ordered mine from swinnerton today for £77

No additional vat or customs on the BikeInn site... think they use a distribution warehouse in the UK. Delivery sometimes takes longer than predicted though. Used them several times without issues.

Whenever changing pads I like to pump the pistons out a bit, clean and lube the pistons, then squeeze them back in. Sometimes do it between pad changes as it keeps the braking performance good. Hoping it'll make the process more satisfying 🙂

Leftfield option, one of them little air wedge thingies. I have never used one on a bike or otherwise so maybe talking total ....

We have three of these Tyre Levers and they're perfect for the job and don't chip anything. Can't imagine spending anything more than that for the job and that's coming from me who loves having random tools for a job I only do once!

The sumart universal bleed block/piston spreader is £39.99 from this dude but not in the country yet

Dave Rome was very positive about these on the Geek Warning podcast recently.

https://www.beautbike.com.au/products/mini-bicycle-disc-brake-piston-press

He says he's going to do a proper review of them soon but basically said they're more versatile than the SRAM ones and don't fall apart like the imitation SRAM ones.

I don't think they ship to the UK yet but hopefully it's a matter of time.

clean and lube the pistons,

SRAM specifically say not to lube the pistons as it actually prevents them retracting properly rather than helping.

It also enables dirt to get past the seal and causes damage to the seal.

That looks to be the Sumart one rebranded. Out of stock currently.

Worth noting that you need two for 4-pots and even then they may not fit (eg Magura).

My standard issue table knife/tyre lever/screwdriver/whatever's to hand will continue to be used I think.

Use a worn down set of pads and an old piston retraction tool. Think it cost me £5 back in 2010.

Never let me down and not damaged any pistons yet.

A bit like this but it's wider for 4 pots

https://www.ebay.co.uk/itm/305761481528?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=hv5brc2stgc&sssrc=4429486&ssuid=eMMoTPPlT7y&var=&widget_ver=artemis&media=COPY

Super cheap alternative,  search Fuel Vacuum line pliers on ebay, about £6. Work a charm.

https://www.ebay.co.uk/itm/395314018767?_skw=fuel+vacuum+line+pliers&itmmeta=01JESA0FHJ03KERDEBZB193CAS&hash=item5c0a8d39cf:g:1rMAAOSw~W9kDDpB&itmprp=enc%3AAQAJAAAA0HoV3kP08IDx%2BKZ9MfhVJKl9RDLDHlCDGAabAhe8DhXVb54%2FRa995Ey%2BzOGb9AKOSLiPaME9vlE5zkTvvfRP%2F6Nyr2nP1C2rzr8GI%2BYMgEWbcXG239fbwYBMBDjCSZGY%2FNJqb%2B1q9Y4MC%2BNJvMWrhwM3%2F4vowzvAlfKS3yElMTDyD%2FSGld0%2F0PQf7PtlBC%2FJ5Z%2BgeNFGgaOde5WpJ6bmPq0dyBueuHtnvTu6YZssugqz2h03taTe5hDs9xAYL3Gnyf4tPW7F0xXcrdtjtg0Mc1A%3D%7Ctkp%3ABk9SR_L4gar2ZA

I 3d printed a pair of wedges; slide them against each other. Worked well, about 50p of filament. Found a few patterns for different caliper widths. (I was using with Shimano calipers).

@cord thanks, I'll try those for £5. Cheers

SRAM specifically say not to lube the pistons as it actually prevents them retracting properly rather than helping.

It also enables dirt to get past the seal and causes damage to the seal

I've never heard that before. Drop of brake fluid worked in and wiped off has always kept mine working lovely. Totally standard practice ime. Never had a seal fail or piston stick.

I’ve never heard that before

Says it in the manual innit..

I've ordered a Sumart from The Cornish Bike Mechanic. Quite possible that is what I'd seen an ad for as mentioned in my first post.

As b33k34 posted I can't help but think the Sram type could put uneven pressure on at least one piston side.

SRAM specifically say not to lube the pistons as it actually prevents them retracting properly rather than helping.

It also enables dirt to get past the seal and causes damage to the seal

So, it doesn't "really" say that. They probably don't want numpties getting oil or grease on the rotor or pad. Or leaving a sticky mess that dirt will stick to.  Or using the wrong lube and knackering the seals, etc, etc.     Same debate regarding forks: if you know what you are doing, then go for it. If not, then leave alone 🙂

So, it doesn’t “really” say that.

Eh? It quite literally says in a highlighted section “Do not apply DOT brake fluid or grease to caliper pistons”.  Clarified further by saying it may cause rotor rub. It repeats this elsewhere in the manual and a SRAM video I’ve seen explains that the piston isn’t supposed to move in and out past the seal during braking but rather the seal itself flexes in order to draw the caliper away from the rotor.

This is a technical manual not ham fisted amateur guidance so I very much doubt they say that just to prevent overspill.

Anyway, you do what you think is best obv. I’ll follow the manual.

@oceanskipper you are 100% right

The Sumart one is in this week's Fresh Goods Friday which links to a UK seller, which looks like it's a website of the Cornish Bike Mechanic.

I went right through to checkout with one of those Sumart tools (clicking the link for STW goodness) but then pulled out as it’s a lot of money (for me), if I was still working as a bike mechanic I would buy one, however, now I’ve got time to work more slowly and only on my own bikes I’ll stick with the Shimano tool I have. I’m not saying that I will never buy one, it’s a desirable tool in my “cheer myself up” wish list!

The Sumart one is in this week’s Fresh Goods Friday which links to a UK seller, which looks like it’s a website of the Cornish Bike Mechanic

It says its designed specifically for 2 piston calipers so will be of limited use for most brakes these days

Wouldn't you just push back two at a time?

Wouldn’t you just push back two at a time?

It's a bleed block as well so if it only works on 2 pistons its no use for any of my brakes, definitely not worth £40 when a tyre lever will push the pistons back perfectly well and I already have some

Okay, I wasn't intending to use it as a bleed block, just wanted something to push pistons back evenly without damaging anything. Tyre levers ain't up to the job sometimes.

Ok. Thanks. I stand corrected. I'll still continue to pump out the pistons and clean with dot fluid before pushing them back in. I'd rather have the pistons clean and smooth rather than dragging dirt into the seals. But I hadn't considered that the seals flex to return the piston during use. In reality, the way I do them probably leaves very little lubrication on the piston as I push them (easily) all the way in this the clean and flexible seal wipes the fluid away. Then I wipe again.

Again, thanks for explaining. Excellent stuff ?

That question mark is supposed to be a thumbs up

Another thumbs up emoji…. ?

The trick is to clean with isopropyl alcohol rather than DOT fluid/mineral oil/ silicon etc I think, as DOT etc will actually do what you are trying to prevent ie dragging dirt past the seals…

So my Sram brake spreader tool arrived... And it's flippin' ace!!

TBF, I was a bit disappointed when it arrived; the threaded lead-screw wasn't very smooth to wind in or out. I pulled it apart, cleaned the threads and applied a very light coat of lube. That transformed it.

I've used it on Sram 2-pot and 4-pot brakes, and also on the latest Hope 4-pots (Tech 4 / E4). It's worked beautifully on all of them.

Thanks to @oceanskipper for putting me right, I'm now removing the old pads, pumping the pistons out a bit, a quick clean with IPA before diving in with the new tool. The tool makes pushing the pistons back an absolute doddle. Even easier if you give the lever the occasional light squeeze.

No more fannying about with screwdrivers or tyre levers 🙂

I got a Sram knockoff (or maybe Sram is the knockoff) from AliExpress. Think it was about £16 delivered. Does what it says on the tin. I take back what I said about it pushing the pistons at an angle. Now it's in my hands I can see both surfaces remain flat to the pistons as they slide by each other.

Didn't intend to end up with two but I've also got the Sumart one. Probably stick whichever one I like less on ebay, but not tried it yet. It's tiny next to the Sram one, but looks like it should work. I'm not convinced it looks like 40 squids worth of tool.

I've got one of the alexpress sram copies and it is great.

https://www.aliexpress.com/item/1005008170570977.html?spm=a2g0o.order_list.order_list_main.5.21ef1802ceKMJA

If you buy one they aren't supposed to fall apart, but they do. What you need to do is take the head off and screw it in a few turns then put the head back on so it'll top out before coming apart.

[url= https://i.postimg.cc/Nj4ZnRh3/Screenshot-2025-01-05-at-09-56-49.pn g" target="_blank">https://i.postimg.cc/Nj4ZnRh3/Screenshot-2025-01-05-at-09-56-49.pn g"/> [/img][/url]

^ Where did you get the 1"AF Knipex, I could only get metric 😉

^ Where did you get the 1″AF Knipex, I could only get metric

Lol... another great tool that I was sceptical about at first. Think I have 3 or 4 plier/wrenches in various sizes now. I got the genuine Knipex... one tool does metric AND imperial 😉

I really want to know if that  Aliexpress one is for a 4 piston pineapple

That one you bought it does it spread the piston by pushing down from the top like pushing a wedge in?

Where as something like this https://www.aliexpress.com/item/1005005610286620.html? pushes them back square in rather than top down

Hey guys, Jack from Beaut Bike here.

Just wanted to clear up a few questions I saw about our Beaut Bike Mini Piston Press / Sumart UBB-20

Sumart aren't the original designer of the Piston Press, as far as I am aware the aren't the designer or manufacturer of any of the products in their catalogue. They're jacking up prices now and trying to charge a lot more than they are worth imo.

I saw a few people asking if we ship internationally and we do, it's a flat AU$19 worldwide. If you're in South America or Africa, you'll need to contact me so I can process the shipping manually, but if you're in Australia, Europe, North America etc. you can just checkout like normal.

Please let me know if you guys have any other questions 🙂

Ordered a SRAM tool yesterday from Bikeinn for £59.98.I’ve never regretted buying decent tools which generally last forever

Thread resurrection. After a pad change on my G2 4-pots took an exorbitant amount of time ovr the weekend, I'm looking at getting either an official SRAM tool, Aliexpress copy, or one of the new Sumart 4-pot tools. A few quick Qs for the forum:

1. SRAM tool works on both 2 and 4-pot brakes - correct? The design / width looks like it might not push 4-pot pistons back evenly though?

2. Sumart tool users - how is the general quality? easy to turn and retract pistons by hand, or are you always reaching for the 3mm hex?

1. I've used my Sram tool on Sram 2-piston (road) and 4-piston brakes (G2 RSC ). Also used on Hope Tech4 brakes. All good: it doesn't completely cover the full surface area of all 4 pistons but it covers enough of them that the pistons are pushed back smoothly and evenly with little effort. Tried it on some cheapo Shimano 2-piston brakes (BR4xx?) but it would not fit in the calliper. Going back to the plastic tyre-lever method felt terrible!

I've got the Park Tool thing linked above, but rarely, if ever use it now.

Cush Core Bead Dropper levers give a nice amount of leverage, have a wide plastic tip, and once you've used them to get the pistons back, then can be used as a brake block during the bleed. I guess you can also use them as a tyre lever.

https://www.sprocketscycles.com/products/cushcore-bead-dropper?variant=37915338047671&country=GB&currency=GBP&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&gad_source=1&gclid=Cj0KCQiAkoe9BhDYARIsAH85cDOIbnkCP9tHWOpv351RYPA6JxJlHXfB_WSP384oSPvPHpBdjWSgoEcaArReEALw_wcB

I got some of these after a recommendation on the escape collective site:

https://www.etsy.com/uk/listing/1554333966/bike-disk-brake-piston-spreader?click_key=b64c594f40ae64d4264f55306dd6ebd97d439ac1%3A1554333966&click_sum=cc2c5cef&ref=shop_home_feat_2&bes=1&sts=1

The postage is a lot but he does a few other useful bits that can soften the blow a bit.

Haven’t used them in anger but the narrow ones are designed such that you can use 2 sets on the weird magura 4 piston calipers on my cargo bike.