Longer fork on '13 Anthem

[madbradd]

Been pretty inactive on the hub for a bit, but this would be the best place to ask.

 

So I have a 2013 Giant Anthem. It's served me really well, been upgraded a bit over time and it's generally not economical to replace.

That said, I moved from Jhb to Cape Town 2 years ago and while the Anthem was perfectly fine for Jhb, it's a bit lacking for CT. I stay in Tokai, so blessed with riding straight out the door and into some great trails. I'd love to push the fork from the stock 100mm to 120/130mm in 34/35mm.

First question is whether anyone has done this with any amount of success? I'm pretty heavy and realise it's going to change angles and stresses on the frame, and don't really feel like having the frame fail on me.

Second, has anyone converted 100mmTA to boost successfully? I see the easiest is probably Rapide's kit with a 5mm spacer either side of the hub and a 5mm spacer on the brake rotor.

Third, headset change from overdrive to normal? I imagine this isn't such an issue, and obviously a new stem needed...

Would be great to hear if anyone has done this before, or if someone has an fork from an older trance that they haven't been able to offload due to the OD2 'standard'.

[dasilvarsa]

100 to 120 Not a Problem Makes any Hardtail or Dual Suspension Better for Downhill Trails.

What fork do you have ?

A lot of them it's just a matter of removing a spacer on the Air Shaft.

[bullet77]

I had a 120mm Fox fork on my '14 Anthem and it was fine at 95kg. I think it did improve the bike going downhill but not by a hell of a lot.  

[RobertWhitehead]

1) Yes, you can increase the travel but I won't go more than 120mm, I have a friend who had a 2015 Anthem and it worked a treat (he's also heavier) 

2) No, I have not done this before but why would you want to? If you boost in the front you are still going to have non-boost in the back so selling the set will be quite hard

3) Ya, this is quite easy, you just remove the top bearing cup and fit a standard cup with a smaller ID bearing. 

[madbradd]

I have a 100mm fox 32 that came standard. LBS said it couldn't be increased easily unfortunately...

[madbradd]

Why not more than 120mm?

Most forks I see (especially the 120mm and up 34s) are boost. My wheelset is non boost so I want to use the non-boost wheel on a boost fork. 

[madbradd]

1 hour ago, bullet77 said:

I had a 120mm Fox fork on my '14 Anthem and it was fine at 95kg. I think it did improve the bike going downhill but not by a hell of a lot.  

Thanks, worth doing?

[madbradd]

1 hour ago, RobertWhitehead said:

1) Yes, you can increase the travel but I won't go more than 120mm, I have a friend who had a 2015 Anthem and it worked a treat (he's also heavier) 

2) No, I have not done this before but why would you want to? If you boost in the front you are still going to have non-boost in the back so selling the set will be quite hard

3) Ya, this is quite easy, you just remove the top bearing cup and fit a standard cup with a smaller ID bearing. 

Why not more than 120mm?

 

Most forks I see (especially the 120mm and up 34s) are boost. My wheelset is non boost so I want to use the non-boost wheel on a boost fork. 

[bullet77]

16 minutes ago, madbradd said:

Thanks, worth doing?

For me it was. I got the 120 for 4k so not a massive outlay. 

[RobertWhitehead]

17 minutes ago, madbradd said:

Why not more than 120mm?

 

Most forks I see (especially the 120mm and up 34s) are boost. My wheelset is non boost so I want to use the non-boost wheel on a boost fork. 

So let me try and explain with my limited knowledge: it has all to do with the angles, I am sure some of the more experienced guys will chime in and guide us better. Your bike came with a head angle of 71deg. If you put more travel that angle will reduce but everything else will remain the same. This is what I would call "riding a slap noodle". 

These folks explain it better

 

https://mbaction.com/geometry-school-head-on-with-head-angles/

[RobertWhitehead]

17 minutes ago, madbradd said:

Why not more than 120mm?

 

Most forks I see (especially the 120mm and up 34s) are boost. My wheelset is non boost so I want to use the non-boost wheel on a boost fork. 

So let me try and explain with my limited knowledge: it has all to do with the angles, I am sure some of the more experienced guys will chime in and guide us better. Your bike came with a head angle of 71deg. If you put more travel that angle will reduce but everything else will remain the same. This is what I would call "riding a slap noodle". 

These folks explain it better

 

https://mbaction.com/geometry-school-head-on-with-head-angles/

[Jewbacca]

The issue comes with raising the BB and slackening the seat angle 

To be fair, the reality of all of this is that you're probably better off just buying an old Pyga 120mm frame and fork https://bikehub.co.za/classifieds/item/dual-suspension-mountain-bike-frames/418813/pyga120650-frame-rockshox-fork-custom-paint

for not much more money than you would have parted with for a fork.

I have run one of these with 26" wheels. It was pretty fun.

You can then switch out the wheels at a later date.

BUT, this is just me. 

The old XC angles on those Anthems are aggressive. These Pygas were ahead of their time

[splat]

'Over forking' the bike could lead to issues in the warranty department.
Perhaps not an issue on older frame.

In reality, I cant see that an extra 20mm travel would stress the frame out that much...

[madbradd]

1 hour ago, Jewbacca said:

The issue comes with raising the BB and slackening the seat angle 

To be fair, the reality of all of this is that you're probably better off just buying an old Pyga 120mm frame and fork https://bikehub.co.za/classifieds/item/dual-suspension-mountain-bike-frames/418813/pyga120650-frame-rockshox-fork-custom-paint

for not much more money than you would have parted with for a fork.

I have run one of these with 26" wheels. It was pretty fun.

You can then switch out the wheels at a later date.

BUT, this is just me. 

The old XC angles on those Anthems are aggressive. These Pygas were ahead of their time

Might be a better idea. XL and 29er though but I get what you mean... when I bought the anthem the one I really wanted was that Pyga 110 29 but was just not a realistic option at the time.

[love2fly]

I have an older Fox 32 Evo that can't increase from 100mm and a Rockshox which I had extended to 120mm and I alternate forks - go figure....I prefer the slightly slacker head angle (I was told by a notable character in the game and very successful past pro cyclist) that it makes a 1 degree difference to head angle on my 2015 model frame.

I emailed Fox in the USA the serial no and they confirmed it couldn't go to 120mm and my understanding is most RS can and with Fox it depends. Id suggest go for it.

[Jewbacca]

1 minute ago, madbradd said:

Might be a better idea. XL and 29er though but I get what you mean... when I bought the anthem the one I really wanted was that Pyga 110 29 but was just not a realistic option at the time.

20mm won't change anything much, but 40mm it starts becoming a compromise.

An older than now but more modern than then frame is a better investment.

Good luck!