Tan Tan GR040 Build

[EddScott]

Have just ordered a Tan Tan GR040.  This will be my build and ride log.

I've been wanting to scratch the Chiner bike build itch for a while and decided I'd go for a gravel bike build as my commuter.  My commute is only like 3/4 miles at most so very light duties and out with the kids. I have a lovely custom built Ragley Blue Pig for rough stuff and a 2020 Cube Reaction Race 29er which I don't seem to be able to sell - unless I'm giving it away! Surprising given the lack of availability of decent mountain bikes in the UK.  Tempted to strip it for parts, sell what I can and move the brakes and transmission over to a FS Chiner 29er (Hurry up AM831).

Anyway, the GR040.  Dealing with Tan Tan has been fine. I mailed LightCarbon and Carbonda. LC were fine to deal with but could not paint only 1 frame. Carbonda didn't reply. Think I messaged ICan regaring the P1 but didn't get a reply either. No drama, The GR040 has been chosen!  Didn't go too fancy on the paint, grey frame and orange forks.  Ordered full bike, frame, bars and wheelset.  Paid through Ali on a credit card so should have section 75 protection, hopefully.

I've also ordered the transmission. This is where things get a little sketchy

https://www.aliexpress.com/item/1005001452212891.html?spm=a2g0s.9042311.0.0.77384c4dyBcunK

ZRace and Sensah transmission and brakes. The BB ordered is BSA so will pick up an 86 locally.   Wanted to go with a full chiner setup and as I'm unlikely to be taking the bike over the Welsh mountains, it won't leave me stranded too far from home if it all ends up in a horribly oily mess

Will update once things start to roll in.

 

[carbonazza]

You just beat me on this 
I was starting to list the components for a fully Chinese equipped bike and nailed my choice to Sensah shifters derailleur and Zrace DUB crank and brakes too.
The Sensah story is cute: http://www.disraeligears.co.uk/Site/Sensah_derailleurs.html
Just I would put a direct mount (3 bolts), and oval ring.
I look forward to your build and impressions.

[Linsook]

Just wanted to mention my exp with ZRace RX crankset.  The spindle was not long enough for the teeth to lock in place and there was movement in the cranks.  Was really looking forward to using it.  Looks great, well made but unfortunately either I got a flawed unit or the design is defective.

youtu.be/pY9TlRZWycE

Looking forward to both your reviews.

[carbonazza]

Just wanted to mention my exp with ZRace RX crankset.  The spindle was not long enough for the teeth to lock in place and there was movement in the cranks.  Was really looking forward to using it.  Looks great, well made but unfortunately either I got a flawed unit or the design is defective.

youtu.be/pY9TlRZWycE

Looking forward to both your reviews.

Did you take the full groupset?
Is it a DUB spindle and DUB BB?

[Linsook]

Did you take the full groupset?
Is it a DUB spindle and DUB BB?

Yup dub .  The crankset was sold with the BB bought from zrace official store on aliexpress.   Looks like they recently setup their Ali store.  I purchased the other drivetrain parts from separate sellers whoever had better prices.  Everything else is fine.

BB is perfectly fine.  The make and quality of the crankset looks great but I think the design they chose contributed to my issue as it requires some tight tolerances.  If I removed the provided 4.5mm drive side spacer I can lock it in place and eliminate the movement you see in my video but there's no separate preload for bearings and so you can imagine the requirement for precision here.  It needs to lock itself correctly in place while applying the correct load on the BB bearings.  The provided 2mm drive side spacer is too thin, cranks lock in place but no load on bearings so I've ordered 0.5mm dub spindle spacers from wheels manufacturing hoping I can get the right spacing and get this crankset solidly installed.  Need it under 4.5 but greater than 2.0mm.  I'm hoping it works because they are lovely cranks.

I took a digital caliper to my bottom bracket area and it is 68mm dead on.  I don't think the BB is out of spec at least not -+ 2mm so.  So my educated guess is the crank being the issue.

[carbonazza]

Did you try to contact ZRACE through Ali ?
I'm trying to get only the crank, to put a direct mount chainring, they said crank + spider were possible, and answered quickly.

[Linsook]

Did you try to contact ZRACE through Ali ?
I'm trying to get only the crank, to put a direct mount chainring, they said crank + spider were possible, and answered quickly.

Ya somewhat responsive but ultimately no resolution so I opened a dispute for partial return. 

[cst_jpr]

Sensah shifters are crap from what I've seen:



In terms of Linsook's issue, something is wrong with what they've included. You cannot rely on exact tolerances on the BB for bearing preload.
For SRAM they use either a wave washer or a an adjustable bearing preload screw. Either of these would probably fit on the Zrace since its standard 30mm shaft, but not certain.

Of course, if you have access to a lathe or tons of spacers and a bunch of time to screw around and get the right width that can work too.

[carbonazza]

...Sensah shifters are crap from what I've seen...

I didn't rewatch the video, the guy like to talk more than inform 
If I remember well it was an issue on the left lever.
There was a plastic part in the shifter, that would break when cable tension was too high on the front derailleur.

Not only they replaced that piece by a metal one on the new units.
But they sent this part to their existing clients for free.
Someone asked me a build with them, so I'll test them the coming weeks but for me Sensah look to care.

[Linsook]

In terms of Linsook's issue, something is wrong with what they've included.

I wish I was missing something because I'm confident they would have shipped a piece.

So anyway I got it right and solid now with the wm spacer. I removed the left side 2.5mm dub spacer replaced with 0.5mm spacer, removed the drive side 4.5 mm spacer and tightened it all up.  Haven't taken it out for a spin yet but clearances are ok.  What a pain.

[cst_jpr]

Not only they replaced that piece by a metal one on the new units.
But they sent this part to their existing clients for free.
Someone asked me a build with them, so I'll test them the coming weeks but for me Sensah look to care.

If someone can take photos of the internal shifting mechanism and prove its all metal, it might be worth using.
Finding the hundreds of people that bought these shifters on aliexpress (years ago?) and shipping them the part would be difficult task though. Probably why this guy never got the part.

I wish I was missing something because I'm confident they would have shipped a piece.

So anyway I got it right and solid now with the wm spacer. I removed the left side 2.5mm dub spacer replaced with 0.5mm spacer, removed the drive side 4.5 mm spacer and tightened it all up.  Haven't taken it out for a spin yet but clearances are ok.  What a pain.

You can see on the zrace hardrock they have a preload adjustment screw: https://www.aliexpress.com/item/1005001512867484.html
Seller would not know, hell the product may be incorrectly kitted/designed in the first place.

Good to hear its working now. I assume its spinning freely.

[Linsook]

Yup, spinning freely. Working fine. 

[sOKRATEs100]

Any updates regarding the build?

Do you have pics?

[EddScott]

Only update I have is that the frame seems to have got stuck during the "Last mile" delivery phase.

Hasn't moved since 5th Jan.

Got the mech etc. All AliExpress parts. I do know I need a different BB to the one I have but I'll wait until the frame arrives before buying anything else.

[EddScott]

It's arrived!

Frame



Sensah oily bits



Might try doing one of those exploded parts pictures.