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I recently drilled the swingarm on my DHR to lower the BB and slacken the headtube angle. I have read a lot of discussion about this procedure online, and noticed a number of conflicting opinions about what was necessary to make this mod properly. I decided to record the procedure and share my findings with the online dh community. I talked to Turner about the process before starting and received reassurances that they approve of the mod. Knowing how well Turner takes care of their customers, I gathered up my confidence and got out the drill and hacksaw.
My 06 Turner DHR w/ an 06 Marzocchi 888RC2X had a BB height of just over 14.5”, this was w/ 2.5” tires and the fork as low in the crowns as possible. I wanted to lower the BB to 14”. I talked to Greg & David at Turner and the Maxxis team mechanic about the proper offset for the second hole in the swingarm. For the BB height I wanted, an 8mm offset was required. Kircaldie runs his bike lower (mid 13”) and uses a 10mm offset.
The mod requires two bits of work on the swingarm. First, the swinglink mount hole needs to be redrilled back (8mm in my case). Second, the material in front of the original mount holes needs to be shaved down for proper clearance of the linkage.
I started by measuring 8mm back from the original mount hole on the swingarm. I marked the spot to be drilled with a sharpie, and dimpled the center w/ a punch to keep the drill bit from wandering. I drilled the first side of the swingarm, and then used the little axle that the needle bearings ride on in the swinglink as a guide for drilling the second hole. This assured that the mount holes are aligned properly, and was a great tip from the guys at Turner. I found that it was necessary to shave some of the powdercoat to fit the axle further back from the original mounting holes.
The second phase required a hacksaw. I marked out the material to be cut from the front of the swingarm and went to it. My first cut was not quite the right angle, and did not give the needed clearance. I made a second cut at the proper angle and checked for clearance at full compression (remove shock spring etc). I then took a file and some steel wool to the cut part of the swingarm and cleaned it up. I ended up with a BB height of just under 14”.
I am very pleased with the way the bike handles with the drilled swingarm. It took me very little time to adjust to the way the bike behaves, aside from needing to be a bit more careful about where I place my pedals. The DHR immediately felt more comfortable in steep technical terrain. Right after I made the mod, we went to a local race and I got a great chance to evaluate the changes in performance. This was a 3000’ descent down old moto trails that were steep and full of deep ruts and loose rock. I was very impressed with how stable and comfortable the bike felt. I could let the bike run more than before, and I was surprised to find that the lower pedal clearance was less of an issue than I had anticipated. When I first started riding DHRs, I noticed that on steep tech trails I had to make an effort to shift my weight further back on the bike than I had in the past. This mod eliminated that feeling, and added a degree of extra confidence in those situations. I like the lower COG for cornering as well; you really feel like you are inside the bike instead of being above it.
After spending four months riding the modified DHR, I would recommend this procedure to anyone who rides in steep terrain. I have not yet found a situation where I miss the stock setting, although the mod allows for switching between the two mounts.
I would be happy to answer any questions about the procedure….
 

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Lay off the Levers
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That's pretty dammed cool!
It takes guts to do a permanent mod like that. Glad to hear Turner had your back on it.:thumbsup:
I wonder if they'll offer a couple of alternative bolt positions on future production DHRs?
 

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Neat!
Sort of like how the rear triangles components are interchangeable on his other bikes...preserves the purity of the intended design, leaves the door open for the mod-monsters, and avoids confusing anyone not really interested in such things.
 

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Something to check.......

Soulrider,

You also need to check that the swingarm is not hitting the inside section of the bb yoke at maximum compression.

Im not sure what you bike is like (it seems to differ on year model), but on my DHR (04) if i did that mod i would have to shave away material from the bb yoke or off the swingarm so it wouldn't contact at maximum travel as well as what you have done. If you have not done so take the shock spring off and cycle it paying attention to bb area/swingarm contact.

I ended up not opting for the drilling mod, i reduced the travel on my shock 1/4 inch and shortened the eyelet 1/8inch (i have an avy so easy to do). Im sitting at 13.9 inchs bb and 7.8inchs rear travel with an 8 inch boxxer WC and 2.5 minions.

I am still getting used to the way the bike rides. It feels much better on flat out drifting type corners but on slow technical trails i am having a bit of trouble, it tends to want to plow straight ahead. Guess you can't have your cake and eat it too.
 

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cave dweller said:
Soulrider,

You also need to check that the swingarm is not hitting the inside section of the bb yoke at maximum compression.

Im not sure what you bike is like (it seems to differ on year model), but on my DHR (04) if i did that mod i would have to shave away material from the bb yoke or off the swingarm so it wouldn't contact at maximum travel as well as what you have done. If you have not done so take the shock spring off and cycle it paying attention to bb area/swingarm contact.

I ended up not opting for the drilling mod, i reduced the travel on my shock 1/4 inch and shortened the eyelet 1/8inch (i have an avy so easy to do). Im sitting at 13.9 inchs bb and 7.8inchs rear travel with an 8 inch boxxer WC and 2.5 minions.

I am still getting used to the way the bike rides. It feels much better on flat out drifting type corners but on slow technical trails i am having a bit of trouble, it tends to want to plow straight ahead. Guess you can't have your cake and eat it too.
yeah I agree, looks like that square tube going from the lower bearing area of the swingarm to the upper shock mount on the swingarm, could hit the BB area backside at full compression and even on a hard bottom out, looks ok, but looks are deceiving....

why doesn't Turner offer that position in the first place, all it is, is one more hole and some material shaved off the front of the shock mount....anyway, hope it works...
yeah Bro~!!!!!
 

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Discussion Starter · #8 ·
cave dweller said:
Soulrider,

You also need to check that the swingarm is not hitting the inside section of the bb yoke at maximum compression.

Im not sure what you bike is like (it seems to differ on year model), but on my DHR (04) if i did that mod i would have to shave away material from the bb yoke or off the swingarm so it wouldn't contact at maximum travel as well as what you have done. If you have not done so take the shock spring off and cycle it paying attention to bb area/swingarm contact.

I ended up not opting for the drilling mod, i reduced the travel on my shock 1/4 inch and shortened the eyelet 1/8inch (i have an avy so easy to do). Im sitting at 13.9 inchs bb and 7.8inchs rear travel with an 8 inch boxxer WC and 2.5 minions.

I am still getting used to the way the bike rides. It feels much better on flat out drifting type corners but on slow technical trails i am having a bit of trouble, it tends to want to plow straight ahead. Guess you can't have your cake and eat it too.
I made very sure there was proper clearance after the mod. I removed the spring and compressed the shock, then checked all the possible contact points. I also spoke at length with Turner & the Maxxis team mechanic about Kircalie's bike and what their processes was. It was because of previous posts of your's (cave dweller) that I did a lot of research before undertaking the modification.
I have ridden the bike regularly for about four months now after the mod. It has been bottomed more than once in that time, and there has been no contact.
 

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swiss cheese

2WH. Just because a small percentage of riders lower their BB does not mean that is good for production. Keep in mind that the faster riders can ride very low BB's because they either drift the bike or wheely it to change direction. They don't steer it like an XC bike. With a very low BB (sag included) it makes riding through extremely rough spots more difficult with the cranks so close to the ground, so pedaling fast and hard is a parallel skill in addition to the bike handling, so even though the bike may 'feel' faster in corner etc, since the BB is lower there may be less pedaling therefore slower times!

DT

"am still getting used to the way the bike rides. It feels much better on flat out drifting type corners but on slow technical trails i am having a bit of trouble, it tends to want to plow straight ahead. Guess you can't have your cake and eat it too" Cave Dweller quote.
 

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1soulrider said:
Ahh, why not...any excuse to post an action photo....
The DHR in action on a local moto trail. The weather here in Norcal has been awesome for riding lately.
:thumbsup:
nice, we've been having an amazing stretch of weather here to.
 

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Here is my DHR, rear modded to 7.8 inchs using a 9.125 x 2.75 shock

I modded my boxxer air WC's to 7.3 inchs on the weekend to steepen the headangle a tad, rides alot better, easier to keep the front end pinned down in the slow stuff.

BB is sitting at 13.6inchs now, head angle is somewhere between 65 and 66 at a guess. Going to need to watch my pedals :D



 

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cave dweller said:
Here is my DHR, rear modded to 7.8 inchs using a 9.125 x 2.75 shock

I modded my boxxer air WC's to 7.3 inchs on the weekend to steepen the headangle a tad, rides alot better, easier to keep the front end pinned down in the slow stuff.

BB is sitting at 13.6inchs now, head angle is somewhere between 65 and 66 at a guess. Going to need to watch my pedals :D
Man I wish you lived closer...........I'd love to try that thing out.
 

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Great post

DHR's are getting reasonably priced in the market so I decided to pick one up after reading about the drill mod.

This post was priceless when it came time to break out the drill and hacksaw. My one gripe was that I could not find a before/after picture from the same angle to really compare.

Nothing scientific or even particularly precise going on here, so please spare the hate. Just thought a little reference would be a nice addition to a post that helped me out.

Enjoy!
 

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