lowering kit

CDN Duke

Member
Country flag
I'm planning on ordering the T-Rex lowering kit, with kickstand for US$135, or US$65 for just the link. TRex 2015 2017 KTM RC390 RC 390 Duke 390 Loweri

It offsets the upper mount as pictured, requiring aftermarket pipe as it won't clear stock can. The KTM OE kits that drop 25mm are back ordered everywhere until November 23rd. This is more affordable, lowers more, but doesn't include fork springs like the OE kit does.

My questions:

1. does anyone have this kit, and if so, how do you find it?
2. forks only have 20mm range to lower on fork tubes - wondering how that will affect ride quality on the Duke, which is slacker head tube angle than RC in first place.

Any comments?


LL164-15WebDis.1.jpgLL164-15Web2.jpg
 

CDN Duke

Member
Country flag
Ordered the kit this afternoon from T-Rex Racing. Will post up feedback once received and installed.

For reference, does anyone know what's different about the springs in the KTM 90212955044 kit? Are they simply shorter overall length or is the spring rate different too?
 

Biker

Member
Country flag
Have raised the front forks up by about 15 mm and taken the preload off the rear. I weigh about 65 kgs and 5' 6" in height. I do not track the bike but enjoy it for occasional weekend use.
I presume at my weight hopefully this won't affect the handling too much? Also given the condition of roads in India a softer rear setting makes the ride more comfortable.
 

diego

New Member
hi CDN Duke, I'm about to buy the same lowering kit for my rc390. Im 5'3

can you post pics and tell us how does it goes?
 

CDN Duke

Member
Country flag
hi CDN Duke, I'm about to buy the same lowering kit for my rc390. Im 5'3

can you post pics and tell us how does it goes?

will do diego, it'll be a week before it arrives, but I'll get it setup as soon as it does and post an update.
 

CDN Duke

Member
Country flag
diego, I ran into some problems with the T-Rex lowering kit, will be contacting them tomorrow to discuss. Long story short, the link needs some additional clearance to fit shock eyelet and the shortened kickstand isn't short enough... I'll post up a thread with pics and some more detail tomorrow night after I talk to T-Rex Racing.
 

diego

New Member
diego, I ran into some problems with the T-Rex lowering kit, will be contacting them tomorrow to discuss. Long story short, the link needs some additional clearance to fit shock eyelet and the shortened kickstand isn't short enough... I'll post up a thread with pics and some more detail tomorrow night after I talk to T-Rex Racing.
Thats bad news, I ordered kickstand too, what do you mean clearance to fit shock eyelet, do you have some pics?
 

CDN Duke

Member
Country flag
When did you order?

The stuff as it came wasn't usable without modification unfortunately. However, T-Rex Racing said they will ensure all new orders would get the proper pieces...

I didn't have time last night but will make sure I post a review later today.
 

diego

New Member
CDN, I order in september, but Im not from USA, So I ordered to a friend's home direction in Miami, and he is coming to visit in December, so I just need to wait..
 

CDN Duke

Member
Country flag
Ok - get him to open the package, you'll need to return the kickstand for sure, unless you want to modify it yourself. It's possible your link may be ok - I'll post up my thread later and you can compare the piece you/he has. If he's in Miami, it will only be a few days for him to turn around the package - T-Rex Racing will look after it I am sure.
 

diego

New Member
Alright, I posted a detailed review of the T-Rex Racing 45mm lowering kit here: http://www.ktmduke390forum.com/foru...49-t-rex-racing-45mm-lowering-kit-review.html

I'd recommend it but you need to get them to confirm you're getting the link with the relief for the shock eyelet and if you buy the kickstand, that it's a modified one...

Thank you CDN, It gives me an idea about what to do if things go wrong. I am a bit worried about if it will fit with my GPR exhaust (high level albus exhaust), If no, I will have to modify the exhaust tube to get it fit.

Post results in December, I hope.
 

CDN Duke

Member
Country flag
Thank you CDN, It gives me an idea about what to do if things go wrong. I am a bit worried about if it will fit with my GPR exhaust (high level albus exhaust), If no, I will have to modify the exhaust tube to get it fit.

Post results in December, I hope.

diego, get your friend to inspect what he received. For sure, you need an updated kickstand. You may need to get a different link - I'd like to know if yours has the relief in it or not. T-Rex Racing will take care of it for you - they're good with customer service. You don't want to waste your time like I did...
 

ToraTora

Member
Country flag
I've been thinking about you vertically challenged riders. There are better options than screwing up the suspension with these crazy linkage mods that negatively effect the handling of the bike. These lowering kits are very unsafe, and I earnestly suggest that you not put them on your bikes. Really what you want is to lower the seat height without changing the handling. Now a lot of bikes that have a removable sub-frame, and what you could do is fabricate one that places the seat in a lower position. Sure the CG changes somewhat due to this, and yeah the bars are going to be a bit higher ergonomically than would be idea, but you can adapt those as well.

pho_bike_90_re.png

If the bike has a removable sub-frame it's not that big of a deal to make another sub-frame that would lower the seat. But even if the bike doesn't have a removable sub-frame you can mod the frame by cutting off the old sub-frame and welding in a mountable removable one. If you are keen to lose some weight you can make the sub-frame out of aluminum too.

Here an example of a bike where they cut off the sub-frame and fabricated one out of aluminum with a bolt on, and another one where they just modified the steal sub-frame. For these photos below the sub-frames were modded to reduce weight, and adapt more of a race tail section.

2eec67q.jpg

rfLuY8k.jpg

6BHtRiV.jpg

addon.php-10.jpeg

These are to give you some ideas on what you can do. And if you have hesitations like not knowing how to weld, etc. there are plenty of capable folks out there that could make you something like these sub-frames. The big advantage being that you wont be screwing up the handling of the bike and potentially putting yourself in a position where the bike is going to crash because the suspension is all messed up--which is what is going on with these "lowering kits."
 

CDN Duke

Member
Country flag
ToraTora, I appreciate what you are trying to state with regards to modifying the geometry etc, but I would hardly say that the kits are 'very unsafe'.

I think the best kit is probably the KTM OE option, which lowers F&R equally 25mm with shortened shock mount eyelet and springs for the fork. I don't think KTM would offer a 'very unsafe' option for their bikes due to the liability.

However, the KTM kit was not readily available to me unless I wanted to pay full C$ retail, and I actually needed more lowering for my wife. With a bike under warranty, the last thing I am going to do is hack apart the frame. A lower seat is not currently available so the other lowering options are what we have to work with. I felt the link from T-Rex Racing looked to be well designed and a reasonable option. However, I need to figure out how to lower the front a matching amount to retain the stock geometry and that's what I'm currently working on. I was able to raise the fork tubes about 17mm in the triple clamps so currently, it's a bit slacker in the head tube angle. I will probably go with the Tyga ride height adjuster which should allow an extra 3/4" of drop or ~19mm. According to Matt at Forumla390, he recalls it allowing ~1.5" of adjustability, so about half down, half up. So, the 17mm drop I have plus 19mm will make ~36mm drop in the front. I plan to install the R6 shock which will raise the rear a few mm so I should end up about 40mm net drop in rear I think. It's pretty close to even then I think, not far off. The only drawback at this point is reduced ground clearance. Ultimately, once my wife is more comfortable, we can look to remove the rear link perhaps but for now, it will stay lowered.
 
Last edited:

ToraTora

Member
Country flag
CDN you are illustrating many of the issues that come up once you start messing with the suspension. And since one it isn't necessary to get a reduced seat height that way, and two more than a little bit dangerous to do it that way, it really should be avoided.

By the way putting in a better shock (which is a nice thing to do on most bikes) isn't going to make up for screwing up the geometry of the bike.

Even if you could perfectly match the front end height to accommodate the change of height in the rear it doesn't make up for the damage done to the way the rear end will work. Rear suspension needs to have the swing arm have an upwards slope from the rear axel to the pivot. When you mess with this geometry it produces an unsafe bike because the suspension cannot function properly.

Ground clearance too is a factor as bottoming out could induce a crash.

I understand your truck with modifying a frame (I wouldn't call it hacking unless done by someone with a lame skill set) which is why I suggested getting a bike, like the new Duke, that has a removable subframe. Clearly you don't need the lowering kit for you to be able to ride the bike (at least from the photos I've looked at). Your wife while more comfortable at a stop on the bike now has to ride a bike that for many reasons is significantly less safe than it was prior to the mods. That's false security.

Look Tyga actually makes sub-frames for a number of bikes. I wouldn't be the least bit surprised if a number of you vertically challenged folks organized and spoke with them that they could come up with a "lowering kit" that would be accomplished with the seat, and not the suspension. Would this require a different bike? Yeah it would. Which is probably what should have been considered more earnestly before the purchase of the RC. There's no point in having a great handling bike if you are going to ruin its ability to handle.
 

Juju

New Member
Yea I know it's rough. She used to have a 2011 ninja 250 for the past 4years. but she felt in love the the RC390. She manages to ride with one leg but that's not the real problem... she's not using the bike to commute to work anymore because she cant get off. she cant reach the stand when the bike is resting on her other leg.
I know lowering a bike is not ideal and not recommended. but I rather have a lowered suspension and have her being able to get off her bike.
beside she weighs 100lbs and will never take it to the track or drive it hard.
here she is on the rc



Hi, I know this is an old thread but wondering if you had any resolve on this topic? I'm ~5' and I've sat on the rc390 before but it was so high, it felt more like a dirt bike (I couldn't flip my other leg over)- which is fine if I wasn't riding on the street. I really love this bike, but I want to feel comfortable enough to at least be both feet tippy toes. What are your thoughts?
 
Top