Mountain gearing setup for my Silvio

[psychling]

When I first arrived in Prescott, AZ, last July I was running SRAM Rival groupset with a 53/39 up front and a 10 speed 11/28 in the back. I found it too demanding for the hills, as I didn't have my `mountain' legs yet. So I switched to a compact 50/34 and an 11/32 in back.

Now, four months later I feel more confident of my climbing strength and ability so I've returned to the 53/39 up front and am keeping the rear 10 speed cassette 11/32.

Tomorrow I'm off to Congress, AZ, and back. About 88 miles and 9,500 feet of climbing. (http://connect.garmin.com/activity/125123252) I'm feeling pretty carefree about the climbing with this groupset. Part of the reason for my confidence has to do with the nature of the climbing. Most of the ascents are long (5-7 miles) grinds of between 4 - 9%. Those are grinders but they are `doable.' It requires endurance and pacing.

Where a smaller, less challenging gear setup comes in handy is when there are spikey inclines of greater than 10%. Unless one has `flying' inertia from a descent that `pushes' you up most of a steep incline the compact crank is well-advised.

 

[Eric Winn]

Are you still running the

Are you still running the 53/39 and 11/32 SRAM gearing on your Silvio?

I am considering ordering a Silvio and fitting it with SRAM RIVAL using this combination with 165mm cranks. I only have short hills nearby but might encounter bigger and longer hills somewhere down the line. Your current stomping grounds look like fun.


-Eric

 

[ak-tux]

SRAM Compact 52/36 chainrings good mix for all round riding

I think the best all round compact double setup from SRAM is the 52/36 compact chainring set from SRAM red group. It can be fitted to any SRAM compact 110 BCD crankset. If you combine this with an 11-32 or 11-36 cassette and a mid/long cage rear deraillur, you will have the widest double gear range that can tackle difficult climbs and still handle high speed decents without spinning-out too early.

 

[Andrew 1973]

Like SRAM WiFli?

Regarding the previous post. This set-up seems similar to the SRAM WiFli set-up, however WiFli handles a maximum 32T cog. I'm interested in the set up you're talking about. Can you be specific onwhich components pair best?

 

[Eric Winn]

I am more interested in a

I am more interested in a full-size front ring, hence 53/39, as I seem to be a strong hill climber and don't have much problem with a 10% grade using my current 52T ring triple. My thinking is the 11-32 cassette will give me the best match for what I think I can do on a variety of road configurations...

According to the SRAM Rival product page the SRAM Rival WiFLi Rear Derailleur is required for the 11-32 cassette but their regular RD spec is rather vague.

ak-tux, I don't see an 11-36 cassette in the SRAM Rival listing so I'm not sure what cassette you are referring to:

SRAM PG 1070 Cassette
11-23: 11-12-13-14-15-16-17-19-21-23
11-25: 11-12-13-14-15-17-19-21-23-25
11-26: 11-12-13-14-15-17-19-21-23-26
11-28: 11-12-13-14-15-17-19-22-25-28
11-32: 11-12-13-15-17-19-22-25-28-32
12-25: 12-13-14-15-16-17-19-21-23-25
12-26: 12-13-14-15-16-17-19-21-23-26
12-27: 12-13-14-15-16-17-19-21-24-27
12-28: 12-13-14-15-16-17-19-22-25-28
12-32: 12-13-14-15-17-19-22-25-28-32


However, after chatting with John T a bit, I'm leaning more toward the Vendetta with this same SRAM Rival setup.

-Eric

 

[Charles.Plager]

Hi,
I assume he's talking

Hi,

I assume he's talking about a mountain bike cassette (for example, this one). You'd need a mountain bike long cage derailleur, but if you went with SRAM, you can still use the road shifters.

If you want to stay with road components, I think you might be limited to 11-32 (for now). It looks like some of the pro riders are starting to use larger rear casettes on road bikes, so we'll see what trickles down in a few years...

Cheers,
Charles

 

[Eric Winn]

I'll be over at Sheldon Brown's....

Hmmm, I have more to learn about interchangeability of bike components.

If you don't hear from me for a while come rescue me from Sheldon Brown's as I may have gotten lost...


-Eric

 

[Eric Winn]

I'm getting an

I'm getting an education.

These pages have a lot of interesting info:

http://sheldonbrown.com/k7.html#roadmtb

http://sheldonbrown.com/k10.shtml

-Eric

 

[Eric Winn]

Gain ratio and RPM to MPH comparison


Using the Sheldon Brown Gear Calculator to plug in my desired SRAM Rival configuration and then my current MTB DF configuration, which wasn't what I thought it was BTW, I came up with this Gear Ratio (GR) comparison. Since I know what my riding is like on my current gears I can "see" where that current pattern falls into the new gearing configuration. At least I think that is what I'm seeing/doing.

Left grouping is the SRAM road 53/39 + 11-32 10 speed cassette.
Right grouping is my Shimano MTB 48/38/28 + 14-28 6 speed cassette.

I never use my 28T crank ring and the only time I've used the 38T crank ring is on a 10% grade where I drop from 48/14 to 38/14 and that is primarily for comfort. I can usually handle a good bit of this using 48/14.

On the flats and slight inclines I am usually in 48/14 for a GR of 6.4 or 48/16 for a GR of 5.6 or 48/18 for a GR of 5.0. This should be roughly equivalent to the SRAM 53/17 for a GR of 6.3 or 53/19 for a GR of 5.7 or 53/22 for a GR of 4.9.

Gain Ratio
53 39
11 9.8 7.2
12 9.0 6.6
13 8.3 6.1 48 38 28
15 7.2 5.3 14 6.4 5.0 3.7
17 6.3 4.7 16 5.6 4.4 3.3
19 5.7 4.2 18 5.0 3.9 2.9
22 4.9 3.6 21 4.2 3.4 2.5
25 4.3 3.2 24 3.7 2.9 2.2
28 3.8 2.8 28 3.2 2.5 1.9
32 3.4 2.5

Correspondingly comparing MPH at 80 RPM.

Again, on my MTB DF I am typically in 48/14 or 48/16 or 48/18 on the flats and slight inclines which should mean I'm hitting 15.8mph to 17.8mph to 20.3mph. These MPH numbers seem to roughly correspond with my current ride data. My numbers are actually a little lower. I think my cadence is somewhere above 60 but somewhat less than 80 but I don't currently have a way to measure it. Sheldon's calculator option for RPM jumps from 60RPM to 80RPM so I used the 80RPM setting which seems subjectively to be close to what I do but I could be totally wrong.

I currently ride about 21 miles per day for 5 days per week, sometimes 7 days per week. I just started recording data 12 rides ago but have been doing this kind of mileage since early April and so far the data seems to be pretty consistent. I will continue to record and monitor as I want to see what kind of improvement I get when I start riding whichever Cruzbike I end up getting - either Silvio or Vendetta. If I am understanding this correctly, my current typical gear usage should correspond to 53/17, 53/19, 53/22 or 15.1mph, 17.5mph, and 22.2mph or roughly the same as on my MTB DF. Except I would still have 3 higher gears and a bike that would be considerably lighter than the 40 pound beast I currently ride. If I can manage the same output levels on those 3 higher gears, perhaps I can achieve some dramatic performance increases.

I live in Michigan not too far from the National 24 Hour Challenge where Jim and Maria Parker participated this summer and I am getting an itch to give this and other UMCA type riding a try.

MPH at 80 RPM
53 39
11 30.3 22.3
12 27.7 20.4
13 25.6 18.8 48 38 28
15 22.2 16.3 14 20.3 16.1 11.8
17 19.6 14.4 16 17.8 14.1 10.4
19 17.5 12.9 18 15.8 12.5 9.2
22 15.1 11.1 21 13.5 10.7 7.9
25 13.3 9.8 24 11.8 9.4 6.9
28 11.9 8.7 28 10.1 8.0 5.9
32 10.4 7.7

Aug 25 Cyclemeter ride with some friends. There is an 8% to 10% grade running from a bit after mile 17 to a little past mile 18 in the map track.

Charles P. as our resident physicist, am I on the right track here?

-Eric

 

[Charles.Plager]

Hi Eric,
I don't know that I

Hi Eric,

I don't know that I have much to offer based on my physics knowledge. Here's what I do know:

I don't climb hills well. I never climbed them well on my upright bikes (I'm from originally from Illinois where it's flat; I pretty much just don't understand changes in elevation) and I don't climb them particularly well on my Sofrider (although with lots of practice I am getting better). I like having low gears (I changed my 28T granny to a 22T granny and very much appreciated the change). On my Sofrider, the most common problem I now have is running out of the top end (48/11 just isn't enough for some big hills)

If you climb well on your diamond frame bikes, I expect that this will continue on either the Silvio or (particularly) Vendetta. So I'm not worried about your choice of front crank. And I think you'll be fine with an 11-32 cassette.

The only reason to go with a smaller cassette on the rear is to get closer spacing on the gearing. I've got an 8 speed 11-32 cassette and do find that some of the jumps are larger than I'd like. A 10 speed 11-32 will be better and given what you have now, I don't think that will be a problem.

Hope this helps. Cheers, Charles

 

[ak-tux]

@AndrewBaloga, thank you for

@AndrewBaloga, thank you for your post: For 11-32 cassettes you can use SRAM WiFi but for 11-34, 11-36 I was refering to a combination of SRAM Road crankset and a SRAM mountain bike deraillur becuase they have the same cable pull ratios what they refer to in marketing speek as "Exact Actuation". SRAM 1:1 actuation ratio (shifter cable travel : derailleur movement)

So take a SRAM Force compact (110 BCD) and fit with 52/36 SRAM chairings for instance. Then fit a SRAM X9 derailleur (or any other 10-speed SRAM long cage derailleur with "Exact Actuation" Like SRAM XX ) you can then use SRAM XG-1099 or SRAM XG-1080 11-36 cassettes and viola! a super wide-range double "groupo".

 

[ak-tux]

@Eric Winn SRAM 10-speed

@Eric Winn SRAM 10-speed mountain bike cassettes have 11-36 combinations. My understanding, (and I'am not a SRAM expert ) is that the beauty of SRAM 10-speed system is that they are compatible as long as you have a matching derailleur pull ratio and chain width/length. Hence you can mix and match "Road" and "Mountain" gear components.

The following SRAM casstetes offer 11-36 ( in order of increasing cost )

SRAM PG 1030 - MSRP (in USD): $60
SRAM XG-1080 - MSRP (in USD): $280
SRAM XG-1099 - MSRP (in USD): $395

I may have left out a few others

The SRAM 10 Speed rear derailleurs with matching pull ratios (SRAM 1:1 actuation ratio) are:
- All the road ones(Apex,Rival, Force and Red)
- X5 Rear Derailleur (Mountain bike )
- X7
- X9
- X0
- XX
e.t.c

Low climbing gears are determined by the total weight of the bike+rider visa-vis the power the rider can sustain on a given % grade.

For some an 34x32 is low enough, for others 34x34 or even 34x36 is not low enough! Offcourse on FWD bikes traction can become an issue on extreme grades so there reaches a point when extremely low gears are practically not useable. As others have noted before in this forum, below a speed of 6Km/h maintaining balance while pedalling at a high cadence becomes a real challenge.

On the other end, you don't want to spin-out too early either on long descents. Its difficult to maintain a cadence of higher than 110 rpm on a FWD MBB bicycle.

The whole point here is to achieve as wide a gear range as possible while maintaing a double crankset. This is becuase some people, generally, prefer double cranksets instead of triple ones. They are much less troublesome to finetune, narrower(Q-factor) and slighly lighter. What you loose, however is that tightly spaced set of cassette gears. It's a compromise that one has to decide for himself/herself.

I personally would love 52/36 and 11-36 combination though if I had a Silvio.

 

[Eric Winn]

@ak-tux, Yes I was experiencing tunnel vision

@ ak-tux, Yes I was experiencing tunnel vision assuming you could not mix and match between the different product lines. I'm glad you pointed it out as it gives me more options than I thought I had.

I also got my low-end information wrong above. I should have said I am running 48/28 on a steep hill and drop to 38/28 to be able to do it for long stretches in comfort. According to Sheldon, this is a change in gain ratio from 3.2 to 2.5.

Using the SRAM 53-39 / 11-32 would give me a 2.5 gain ratio for my lowest gear in that configuration which matches what I currently use for my lowest gear although I could go as low as 28/28 for a 1.9GR.

The SRAM site is not consistent about displaying their cassette information, sometimes showing 11-34, 11-36, etc without displaying all 10 teeth count and in other places providing full details. Some of those last step or two can be drammatic and seems like it would complicate shifting in some situations. I need to try riding some bikes with those combos if I can find any.

A 53-39 / 11-34 gives me a low end gain ratio of 2.3
A 53-39 / 11-36 gives me a low end gain ratio of 2.2
A 50-34 / 11-34 gives me a low end gain ratio of 2.0
A 50-34 / 11-36 gives me a low end gain ration of 1.9 which matches my current MTB.

Fun stuff but I need some steeper, longer hills to proof test

-Eric

 

[ak-tux]

@Eric Winn  I saw these

@Eric Winn I saw these details for SRAM 11-36 somewhere on the internet:

SRAM PG-1030 11-36 10 Speed

• 
  PowerGlide technology provides super-smooth shifting
• 
  Aluminum spider, heat treated steel cogs, and a durable nickel chrome finish
• 
  11,13,15,17,19,22,25,28,32,36
• 
  395 grams

The last two sprockets have some big jumps but all in all it looks like reasonably good spread of gears.

 

[ak-tux]

Spin Doctor Tech Tip – 10 Speed MTB Drivetrain Compatibility

Very Nice article on SRAM and Shimano10-speed MTB compatibiliity:

http://blog.performancebike.com/2011/01/28/spin-doctor-tech-tip-10-speed-mtb-drivetrain-compatibility/

Let me quote the interesting part:

3. In a switch, SRAM's 10-speed mountain bike derailleurs (XX, X0, X9 & X7) are now compatible with their 10-speed road shifters (Red, Force, Rival & Apex). So you can use Rival shifters with a XX rear derailleur and wide range X7 10-speed cassette for mountain centuries.


4. And the bummer, their 10-speed MTB derailleurs are not compatible with their 9-speed MTB drivetrains!

......

... In a switch, Shimano's D-S( Dyna-Sys ) 10 speed rear derailleurs (XTR, XT and SLX) are NOT compatible with Shimano road shifters nor with other non-D-S MTB shifters.

 

[John Tolhurst]

IF you think about the lack

IF you think about the lack of aero to overcome when you are climbing, then the 32 36 jump is not that much. Where as 10 to 11 when you are looking for 11/10 cubed more power to push the 10 tooth sproket, now that is actually a big jump.

 

[ak-tux]

Yes, you are right John! Come

Yes, you are right John! Come to think of it, the jump from the 11t to the 13t sprocket is where the real big jump is alt="enlightened"

Using Sheldon's gear ratio calculator also confirm this: Assuming a 52T chainring and a 10-speed 11-13-15-17-19-22-25-28-32-36 cassette will give the following:

Sprocket Gain Ratio % change
11 9.3 18.2 %
13 7.9 15.4 %
15 6.8 13.3 %
17 6.0 11.8 %
19 5.4 15.8 %
22 4.7 13.6 %
25 4.1 12.0 %
28 3.7 14.3 %
32 3.2 12.5 %
36 2.8

 

[John Tolhurst]

At the tall end, you need

At the tall end, you need closer ratios because of the big power increases that aerodynamic drag ask you for. And then you need a big overall range. And then you need a triple, or you need to drop a lot of weight. Drop 20% of weight of bike and rider and you don't need that last 20% of low gearing. Or you live with lumpy big shifts at the top because you don't mind not being able to control your effort right at the threshold. Compromises, all of it.

 

[Eric Winn]

@ak-tux What inputs did you use?

@ak-tux What inputs did you use for your last post for wheel size and crank lenth?

-Eric

 

[ak-tux]

@ Eric Winn
Gear chart using

@ Eric Winn

Gear chart using Gain Ratios for 52 chainring with 11-36 cassette

For 700c X 25 / 25-622 tire with 170 mm cranks

With Custom Sprocket(s) Cassette 10-speed 11-13-15-17-19-22-25-28-32-36