rafiki530

So I have heard good things about this hub: https://www.amazon.com/SRAM-36h-Autom...pr_product_top

more information about the hub can be found on sram's website: https://www.sram.com/sram/urban/products/automatix

I have wanted to build a wheel from one of these since I saw it on bike rumor a few years back. Does anyone ride one, what do you think?

In one of the reviews someone has posted that the OLN is 120mm but when I look at the product description they say 130mm? Is the axle width 120 or 130 I want to know before I buy one for my bike which is spaced at 120.

hockeyteeth

Meh. I have had to deal with Shimano's autoshifting 3-speed drivetrain (https://www.parktool.com/blog/calvins...oasting-system) and it was quite lame. While the centrifugal clutch on the SRAM hub is quite a bit simpler than Shimano's computer-actuated shifting, it just sucks to ride a bike that shifts automatically. Especially when you are hovering around the range of the up and down shift. A kickback 2-speed hub would be cool: https://www.bunchobikes.com/auto.htm

rafiki530

my that looks like a very complex system for the shimano. I just like the idea of just hoping on a bike and not having to worry about changing gears, that's why I like fixed gear, you don't have to concentrate on so many little things and can concentrate on your surroundings instead.

DanBell

I'm not sure if this thread belongs in FGSS, but what about the NuVinci N360 variable gear hub?

rafiki530

that is an interesting hub neat concept. I guess I could post this thread somewhere else where people may find it more appropriate, I figured more people here might have had experience with this hub based on the fact that many users here ride bikes with horizontal dropouts.

rafiki530

question about rims, I know that I need 700c wheels for my bike but when it comes to rims does width and length matter. Also the material they are made from. The sram automatix is fairly heavy compared to other hubs that I've built with and was wondering if deep dish rims would be worse than say shallower rims like a mavic open sport.

Can you use carbon rims with a heavier hub say 50mm carbon rims? I ask because a former roommate has one and would be willing to sell it to me for 120 dollars. The rim looks fairly solid (unbranded but new and never used) I thought I would ask before buying it from him.

europa

The hub's sort of irrelevant to the rim. You'll just have to put up with the weight of the hub, that's the price you pay for the gears, but the old rules about rotational mass still apply out at the rim. Just choose the rim appropriate to your needs and lace it to your hub. For what it's worth, modern rims are so good that just as generous spoke counts are no longer needed for a strong wheel, you don't need to worry about the rim being strong enough provided it's not a track or pure racing rim for use on suburban roads.

rafiki530

for sure thank you for the help. I will be getting parts in next week. Ill provide updates for anyone interested in the hub.

europa

Course we're interested in updates - it'll either be informative or entertaining

Xgecko

since no one answered your question I will, the axle is long enough to fit in a 130mm rear triangle and comes with a set of spacers/washers to space out the stock 120mm spaced hub in order to do so. Its a nice hub, I had a Sturmey Archer kickback for 2 years and when I switched to the SRAM automatix coaster I was ecstatic and how much better the ride is. I laced mine to a CR18 but I wanted a lot of float for my trashed new england roads

bikemig 

I've been thinking of building a 2 spd rear wheel like this for a surly 1x1 (I guess it will be a 1x2.. Why is the SRAM automatix so much better than the SA kickback? Also were you using the coaster brake version?

Xgecko

My reasons are purely subjective but I will contrast the two for you...I have a SA freewheel and a SRAM Coaster though I have ridden both hubs in both configurations......if you are planning on a Coaster the SA hub is a nightmare (IMO), every time you hit the brake it changes gears. Freewheeling its good and you get a sense for how and when to shift in a few hours of riding. The SRAM shifts at 11mph perfectly. You can spin at 15mph in the low gear on the SA where the SRAM is in high. The SRAM stays (locked) in high even at low speed until you relax/coast and then it drops to low gear. This is big deal on hills and something I have had to think about since I switched; I grocery shop by bicycle and climbing with a heavy load requires a bit of planning as I live on a hill with a 9%-10% grade. The Kickshift takes a few hundred miles to really settle and be smooth though it isn't as smooth as the SRAM out of the box. It is really easy to tell which gear you are in on the SA coasting, it buzzes louder in high. Some other things to think about the SRAM only comes in 36Hole the SA in 32H or 36H, the SRAM comes in one color, silver with a colored sticker, the SA in Silver or a durable painted black. The SRAM Coaster weighs abut the same as the SA freewheel 950grams. the SA Coaster is like 1.5kilo's and the SRAM freewheel is 750grams if I remember right but you don't buy these hubs if you are a weight weenie. Gearing wise I believe the SA hub can take everything from a 13T to a 22T read cog and the SRAM is limited to 15T as its smallest cog, this is because of how the SRAM is constructed so take this into account should you decide on a SRAM hub. The cogs are $3-$5 and IMO SA makes the best 3 tab cogs so it's not expensive to play with gearing. Make sure you buy a couple of retainer rings and it helps to have a set of Circlip pliers. If you go with a coaster neither hub comes with a brake clamp, annoying but some old inner-tube and a trip to HomeDepot plumbers dept. solves that.

bikemig 

Cool, I was thinking of a coaster brake for a winter brake with a SA drum/dyno hub up front. It looks like SRAM is the way to go then.

europa

Be careful with SA's claims about different spoke counts. I've just been through the exercise of buying a SA S3X. They did come in 32 and 36 spokes, but then the 32s disappeared and were eventually dropped from SAs website. Similarly with colours, when I was finally able to buy mine, you could only get the silver hub in 120. They're a mad mob, probably because they're a small manufacturer ... and mad.
Also, be warned that 36 holes restricts your choice of rims these days.
It's all stuff that can be worked around but can be rather frustrating, especially if what you can get doesn't match what you've set your heart on.

As for buying the things, Scrod looked after me very well and did a fair bit of searching to find what and wasn't available. Pricing was good too, especially with the effort he put in.

rafiki530

Okay update on the build I got all my parts and finally some free time to get started but first I will post what I have and give you my first impressions. I'm trying to keep this build under 250 dollars we will see.

Ill start off with the rim it is a 50mm full carbon clincher I bought it off a friend for 120 dollars looks like it's in good shape and it's very light.

From the spoke calculations I made I determined that I will be using a spoke length of 256mm, after looking online I settled on buying some red flat bladed spokes from a company called cn spokes. here is their website if you are interested in their products. https://www.cnspoke.com/products/Spoke_CN/spoke.htm the spokes I bought were the mac areo 494 spokes. the total cost for 36 spokes was around 46 dollars.

I bought the sram automatix hub off amazon for around 69 dollars and it came with free shipping. My first impressions of this hub were good, the hub flanges look very solid, It is a bit heavy though I wouldn't say it weighs more than my sx3 but it is a lot heavier than the sram torpedo. I am exited to see what this hub can do and will post more info as the build comes along.

europa

OMG, it's gonna happen

Keep us posted

Xgecko

wow that's about as different from mine as one can get, carbon rim, red spokes that's flashy

rafiki530

So I have ran into some delay, while looking at the hub and the spokes i realized that they don't quite fit it's not a huge difference maybe half a millimeter but it's enough to stop the spoke from going through the hole, if I really decided to pull I could probably get one through but then the paint from he spokes would flake. So Instead of doing that I took my dremel tool and shaved a little bit off toward the center of the hub, to do this i took a metal cutting bit and began to cut the holes, not quite slotting the hub but making just enough room to accept the spoke. In the pictures below you can see the before and after.

europa

Hmm, 36 holes, then there's the front wheel to build, let's be mean and add another 36. What's the bet he can't enlarge 72 holes without screwing one up?

Hot tip: Save the Scotch for AFTER the job, not before or during

rafiki530

Okay more updates on the build, the wheel has been laced I'm not going to really go over the details of lacing a 36h wheel since it has been talked to death here and other places, if you want some info you can go here: https://sheldonbrown.com/wheelbuild.html
or watch this nice video (out of all the videos on you tube I like this one the best) : https://youtu.be/AOI3uBztvHc anyway...
Here is the hub with the spoke holes finished from drilling, as you can see I didn't necessarily slot them but drilled out from the existing holes. I drilled toward the center of the hub flange (drilling into a hub away from the center of the hub or hub flange can weaken the integrity of the hub, the drilling of spoke holes in any hub can ruin the performance of the hub, DRILLING OR MODIFYING ANY HUB WILL PROBABLY VOID THE WARRANTY OF SAID HUB, SO BUILDER BEWARE.) for this project however I opted to drill into the hub based on my own judgement and used a jig to do so, the holes came out nicely and evenly, and are just big enough to accept each spoke.
getting started....
halfway there...
and now I'm finished with the lacing.. Now on to the hard and tedious part which is the truing of the wheel. I will keep providing updates as they occur. Thank you for the responses and support.

europa

Oi, not fair, teasing us with attachments and then mucking up the links so we can't see them



Done it meself, never did work out what I did wrong

Xgecko

if you know anyone with an electronic guitar tuner you can get the tension uniform by tone. My issue was getting it round, straight was easy.

Skankingbiker

I have this hub and I am not a huge fan. To start with, the shift point is insanely low and the bike autoshifts at about 5mph---I called it a "granny assist" when I first rode it. To remedy this, you need to take the hub apart and adjust one of the springs. Second, the hub is not sealed and seems to accumulate dirt/grime fairly quickly. Third, the hub is very finicky as far as locknut adjustment/tightness is concerned. Fourth, the hub drops back into low gear when coasting. Thus, one unforeseen consequence of adjusting the shift point to something more useable is that the hub constantly switches low to high. Fifth, to climb a hill, you have to stop pedaling, allow your speed to drop and then hope you are going slow enough to drop into the low gear while pedaling.

On the positive side, the hub is pretty quiet, doesn't really "ghost shift", the shift point is predictable, and shifts are pretty smooth (no "clunk")

BruceMetras

I just came across this thread .. I run three different bikes with the Automatic 2 speed.. one with one of the much earlier Sachs units (basically the same mechanicals of the SRAM) and two with the SRAM units.. I modified all to shift at a higher speed (usually at around 14mph) .. so far through the years, they have been excellent.. I had the SA kickback and had lots of issues and warranty replacements.. the SRAM/Sachs units have been stellar.. Here is my titanium road frame

Douglas Titanium





Moulton TSR-2 with SRAM Automatix






Dahon Mu Uno with SRAM Automatix and belt drive

Xgecko

this may or may not be useful to you, I will probably play with mine come spring when I clean and lube my hub

adjusting the shift point