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NSMB - 2021 - Hardtail Thread

Sept. 29, 2021, 2:14 p.m.
Posts: 2
Joined: Feb. 24, 2017

Just curious what everyone is running for tires? Now that things are getting wetter the Bontrager XR2's on my procaliber are not cutting it.

Sept. 29, 2021, 3:58 p.m.
Posts: 689
Joined: Sept. 10, 2012

Posted by: mountainmike

Just curious what everyone is running for tires? Now that things are getting wetter the Bontrager XR2's on my procaliber are not cutting it.

29 x 2.6" DHF/DHRII Maxx Terra EXO. Tannus Tubeless in the rear. 30mm IW rims. I want to be able to put 30K of paved riding on them to get to/from the trails each ride so I am not running a softer compound.

Sept. 30, 2021, 2:27 a.m.
Posts: 7
Joined: Jan. 18, 2019

Posted by: Chasmoftheclam

Thanks all! What great responses. I'll take a look for the Yess tensioner @Heinous mentioned as my frame does have the ISCG 05 mounts. I'm intrigued by this solution!

You can also play with cogs, rings and half link chains to possibly get a chain length and gear ratio that works without a tensioner.

I'm sure a quick Google search could bring up a database someone nerdier than me has made of chainstay lengths and compatible gear ratios....


 Last edited by: GiveitsomeWelly on Sept. 30, 2021, 2:28 a.m., edited 1 time in total.
Sept. 30, 2021, 6:37 a.m.
Posts: 40
Joined: Feb. 9, 2019

On the topic of singlespeed tensioning solutions:

I recommend running a single half link in a compatible chain instead of a half link chain (KMC Z1 and HL1 work well together, I tested the 1/8" versions, but I bet the 3/32" variants would work too). Way cheaper and you have half-links for life, plus any durability concerns people regularly voice about half link chains no longer apply to you :)

For magic gear ratios, there's this here gem of early 2000s webdesign: https://eehouse.org/fixin/fixmeup

I can also second that a BB mounted chain roller works nicely as a fixed position tensioner (I used a Blackspire Stinger, clamped by the BB, with no issues).
Similar fixed wheel tensioners exist to be mounted instead of a derailleur (DMR make one if I remember correctly).

Good sprung tensioners are available from SB-One (mounts on the derailleur hanger, clears only a 17t, but is indeed a nifty piece of kit), and I think I saw someone use a pinion tensioner meant to be mounted on the Gearbox hacked to some ISCG tabs. I've heard mixed things about the Rohloff and Alfine tensioners. When I last tried to source a Yess tensioner I couldn't find one over here in europe, sadly.

Finally, there's eccentric BB conversions for BSA frames at least (I can only think of the Trickstuff Exzentriker), but that's expensive, doesn't give much tensioner range, and restricts you to run 24mm cranks (though I personally don't see an issue in that).

As a curiosity, I'll also add that Ghost Rings are a thing: http://rollinginboston.bostonbiker.org/2012/04/08/installing-a-ghostring-on-a-single-speed-or-internally-geared-bicycle/
Not sure I'd want that on an MTB though.


 Last edited by: twk on Sept. 30, 2021, 6:43 a.m., edited 1 time in total.
Sept. 30, 2021, 7:41 a.m.
Posts: 1
Joined: July 29, 2013

You'll likely need a 1/8 chain if using a half-link. Most narrow-wide chainrings will not fit a 3/32 half-link.

Sept. 30, 2021, 10:05 a.m.
Posts: 40
Joined: Feb. 9, 2019

Posted by: geraldooka

You'll likely need a 1/8 chain if using a half-link. Most narrow-wide chainrings will not fit a 3/32 half-link.

That is a good catch! most (all?) 1/8" chains clear most (all?) N/W chainrings, even narrow links on wide teeth. But with adequate tension, and no sprung tensioner I find dedicated singlespeed chainrings with even tooth profiles to be cheaper and just as reliable, which again opens up the possibilities for narrower chains.

Oct. 9, 2021, 6:22 p.m.
Posts: 689
Joined: Sept. 10, 2012

Well I finally did it...I'm going to ride a SS rig this winter as my main bike. I blame Andrew. I decided to swap the parts from the Cotic BFeMax large frame to this Pipedream Sirius Long [aka medium] frame so I could leave my Daambuilt hardtail setup in gravel/road/bikepacking mode. I don't have a road/gravel bike so when I want to explore someplace on the map from my door that's my ride and I didn't want to lose that capability.

This Pipedream had the benefit on being in stock and easy to order as well it fit all the parts I wanted to swap over. The Sirius was designed for a 100-120mm fork. The MRP Ribbon Coil I had was convertible 140-160mm so I lowered it to 140mm and slapped it on. All Pipedreams have short head tubes so I threw on as many spacers under the stem as I could and then added 70mm rise bars as well. This gets the grips approximately level with the saddle on the unsagged bike.

Unsagged HTA is ~62 deg based on my phone and the unsagged STA is 75 deg. Tires are 29 x 2.6" DHF/DHR on 30mm IW rims. CS are 425mm at min length and I had to add a few mm to that to tension the chain with the sliders. I wanted a smaller front centre, smaller rear centre and smaller saddle to bars distance. I got all three.

Gear ratio is 30 x 22T.

My initial riding has been on my local rolling XC trails. Sizing down has got me the agility back that I missed when riding the Cotic. I don't have to be going crazy fast to get the bike into the air or on its rear wheel. It loves to slice and dice between the trees and carve turns. I feel much more in control vs. being along for the ride. Riding SS has been very engaging and the easy rolling terrain is perfect for one gear...as you would expect.

I'll head to Cumby tomorrow and ride some of the lower trails to see how that goes with one gear.

My initial thoughts are that the sizing and geo of this frame are a good match for where and how I ride. I suspect that whatever capability I lose by having a smaller less stable frame I'll get back by feeling very confident and in charge of the bike. I've got no idea how I'll feel about SS when I head to the real mountains, but there is only one way to find out. I can throw a 28T ring on the bike if I need a lower gear...especially for the first month or two, but we'll see.

Frame flex is key for my enjoyment of a hardtail. The Sirius is flexier than the BFeMAX and feels close in flex to my Daambuilt. The BFeMAX wasn't what I would call overly stiff, but I am happier on a frame with more flex than that so the Sirius is a good fit in that regard.

As with all my winter bikes it's got full fenders and frame bags so I can do a long ride packless in any weather and not hate life.

Build Kit

  • Sirius S5 frame in silver [Long size]
  • 140mm MRP Ribbon Coil
  • Hope hubs + Velocity Blunt 35 wheels
  • Maxxis DXF/DHR 29 x 2.6" tires with a Tannus Tubeless insert in the rear
  • Shimano Deore 4 piston brakes 200mm/180mm rotors
  • 30T x 22T SS drivetrain
  • RF Next R 170mm cranks
  • RF Chester pedals
  • I9 35mm stem
  • Ergotec 780 x 70mm rise bars with Ergon grips
  • 9point8 150mm dropper
  • WTB Pure saddle
  • RRP front fender
  • Mudhugger rear fender
  • Rock Bros frame bags
  • PDW DT splash guard
  • Fabric bottle

 Last edited by: Vikb on Oct. 9, 2021, 6:35 p.m., edited 2 times in total.
Oct. 9, 2021, 8:13 p.m.
Posts: 1073
Joined: May 11, 2018

Nice ride Vic. Glad you are enjoying it. Not sure what gear you are riding but I suspect you will be fine riding almost anything you want in cumby. I wouldn't limit your route based on the single speed. Worst case scenario, you walk up a steep section. Generally, once you get the hang of ss (if you haven't already) you start to read the nuances of the terrain and sprint into and up the slightly steeper portions of a climb and build a bit of recovery into the less steep parts. Personally, I choose my gear so that I can climb most any climb at the cost of too low a gear for some flats and downhills. I find most people waste a lot of energy when riding with gears. I can generally keep up or even ride faster on ss (on technical terrain)  by maintaining my momentum and using short bursts of high cadence spinning. 

Let us know how it goes. Your rig looks like a lot of fun!

Oct. 12, 2021, 5:26 p.m.
Posts: 1073
Joined: May 11, 2018

Does this need any explanation or comment?

Oct. 12, 2021, 9:11 p.m.
Posts: 146
Joined: Feb. 24, 2017

Posted by: RAHrider

Does this need any explanation or comment?

Always. 

Ti? Why are there bosses on the seat tube? Wheelsize? Angles? Are Turner still around, or is this NOS?

Oct. 12, 2021, 10:01 p.m.
Posts: 689
Joined: Sept. 10, 2012

Posted by: velocipedestrian

Ti? Why are there bosses on the seat tube? Wheelsize? Angles? Are Turner still around, or is this NOS?

https://turnerbikes.com/collections/nitrous

Oct. 13, 2021, 8:13 a.m.
Posts: 801
Joined: Jan. 31, 2005

Turner only make Ti hardtails now? And not even manufactured in the USA. As someone who had a peak RFX in 2000 this development is a little sad.


 Last edited by: craw on Oct. 13, 2021, 8:15 a.m., edited 2 times in total.
Oct. 13, 2021, 1:40 p.m.
Posts: 1073
Joined: May 11, 2018

Posted by: craw

Turner only make Ti hardtails now? And not even manufactured in the USA. As someone who had a peak RFX in 2000 this development is a little sad.

:(

I couldn't figure out where they are made. That is so sad. I can't figure out why people want to pay that much for an overseas non-custom bike. The chromag ti as well as the knolly rigid bikes all fall into that category. 

Maybe one day there will be a bigger push to bring manufacturing here.

Oct. 13, 2021, 4:08 p.m.
Posts: 689
Joined: Sept. 10, 2012

On that note I noticed that Naked has gone full Ti for their bike options**. Makes sense I guess.

** - you can have steel if you really want, but the cost for steel is the same as Ti.

Oct. 13, 2021, 7:11 p.m.
Posts: 905
Joined: March 15, 2013

Hoooooly

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